Jiminy-py

Gym Jiminy, and especially the pipeline design tools, have been heavily refactored to improves performance. The keystone was to share references to avoid copies and memory allocations as such as possible. It also removes automatic clamping of actions/observations. It is up to the user to re-enable it, e.g. using gym wrappers. In addition, the efficiency of computationally demanding gym space helpers and provided PID controller block have been greatly enhanced. 3 times speed-up is to be expected.

Improvements:
* [core/python] Add extra parameter to convertToPython to return either reference or copy.
* [python|gym] Add unsafe set handle for controller to avoid of the cost of handling initialization separately.
* [gym] Refactor observation block chaining to use references for efficiency.
* [gym] Refactor GoalEnv to make it easier to use.

Bug fixes:
* [core] Fix segfault in some cases when 'start' method fails.

Miscellaneous:
* [core] Print error and warning messages on stderr instead of stdout.
* [core] Always remove robot lock when calling Engine.Stop.
* [core/python] Preserve constness of systemState Python bindings.
* [gym] Use np.core.umath.* directly in helper methods for efficiency.
* [gym] Reorder branches in helper methods to find most frequent case first.
* [gym] Add engine/stepper_state/system_state/sensors_state proxies to speed-up attribute lookup.
* [gym] Use 'dict/{}' instead of OrderedDict in 'step' method and calles for efficiency.
* [gym] Observe state as a dict instead of array to avoid memory allocation.
* [gym] Do not clip observation/action by default for efficiency.
* [gym] Pre-compiled PID law for efficiency.
* [gym] Rename _clamp in clip for consistency with numpy.
* [gym] No longer use 'encoder.fieldnames' to define state and pid target fields.

This release improves the general stability of jiminy_py, and especially the viewer. Additionally, it adds support of color names (e.g. 'orange') instead of RGBA color code for convenience.

Improvements:
* [python/viewer] Do not refresh camera pose automatically if no camera motion nor travelling.
* [python/viewer] Add support of string color to 'play_trajectories'.

Bug fixes:
* [core/python] Fix segfault when reading log without data.
* [python/simulation] Fix exception handling at reset.
* [python/viewer] Fix color handling for robot with reference material.
* [python/viewer] Fix exception if viewer arg is None for play_trajectories.
* [gym/examples] Fix tianshou rendering update period.

Miscellaneous:
* [misc] Fix telemetry format doc.
* [python/simulator] Throw error and replaying simulation without data.
* [python/simulator] Remove useless check for '__getattr__'.
* [python/viewer] Ensure unique robot names during replay.
* [gym] More explicit error message for 'set_value' helper.

Jiminy_py viewer recorder is hanging on Windows 10 for Python 3.6 because the subprocess creation is silently failing.

This release improves the stability of the viewer. In addition, it introduces a default color cycle when replying simulation for multiple robots at once (7 different colors).

Improvements:
* [python/viewer] Add default colors if multiple robot are replayed at the same time.
* [python/viewer] Redirect meshcat backend std_err to devnull to avoid flooding main thread.

Bug fixes:
* [core] Fix jiminy.Robot multiple initialize.
* [python/viewer] Fix edge case make the robot not appear in viewer if closed manually and reopen with same name.
* [python/viewer] Handle backend process kill timeout exceptions.

Miscellaneous:
* [misc] Disable automatic forward compatibility of numba to avoid potential install failure.

This release adds camera motion planning capability, and significantly improves the stability of log plotting and replaying utilities.

New features:
* [python/viewer] Add new camera motion planning when replying trajectories.

Improvements:
* [python/viewer] Enable to change urdf color in already instantiated viewers.
* [python/viewer] Enable to set relative camera pose in Meshcat.
* [python/viewer] Rework travelling to be more flexible and more sure only is enable at a time.

Bug fixes:
* [python/simulator] Catch more exceptions.
* [python/simulator] Ensure proper argument forwarding for 'replay' method.
* [python/simulator] Fix bugs and glitches for 'plot' method. Disable inter-tab sync of x-axis (time).
* [python/viewer] Fix global attributes not reset if backend viewer is closed by user manually.
* [python/viewer] Fix color not taken into account in some cases.

Miscellaneous:
* [python/simulator] Forbid calling 'render' method if no simulation running.
* [python/viewer] Improve typing of 'play_trajectories'.
* [python|gym] Move 'replay' method from 'BaseJiminyEnv' to 'Simulator'.

This release introduces a new position/velocity bounds model that should be both more strict and more stable numerically. It acts at kinematic level instead of dynamics and absorb more energy to reduce bouncing effect. In addition, motor inertia is now taken into account for any type of 1dof joints, and the associated custom `aba`, `rnea` and `kinematicEnergy` methods are exposed in Python.

New features:
* [core/python] Expose custom pinocchio algorithms to support motor inertia.
* [core] Bounds limits efforts are now proportional to joint's subtree inertia.

Improvements:
* [core] Remove blending factor for joint bounds because it does more harm than good.
* [core] Add support of translation joints.
* [core] Support any 1D type of joints for rotor inertia.
* [core/python] Ensure constness when passing C++ variables to Python handles.
* [gym] Disable engine timeout if debug enable.

Bug fixes:
* [core] Fix edge case when reading log after calling start and no actual data is available.
* [python/simulator] Reset viewer when calling 'reset' method to avoid corrupted viewer internal state.
* [python/viewer] Various minor bug fixes.

Miscellaneous:
* [core] PRINT_* macros do not terminate by ;
* [core] Use C++17 constexpr in some places.
* [core] Add constexp 'is_pinocchio_joint_*_v' to determine the type of joint at compile type.
* [core] Improve get joint type getter to use joint visitor instead of string comparison.