Annarchy

* Issue 55: Populations and projections can now save/load their variables into/from Numpy `.npz` files instead of pickled binary text files.
* Bugfix (CUDA): modified transmission flag was ignored on projections.
* Bugfix: memory leak when using Monitors in parallel_run().
* Added raster_plot, histogram and so on outside the monitor for offline analysis.
* Improvements on memory management.

* Monitor: added new argument ``period_offset`` to define the offset within a period to record. The default argument is 0ms to match the previous behavior (at the beginning of the period).
* Issue 54: when generating a report, possible subfolders are created before writing the report file
* CUDA now supports usage of post.sum() respectively pre.sum() in synaptic equations.
* CUDA ``SpikeSourceArray``: wrong update of events on the GPU device led to wrong results.
* Various bug fixes and improvements.

* Merged pull request by ilysym to improve OpenMP efficiency. Thanks Ilya!
* Added a ``power(x,a)`` function to replace the slow cmath pow(x,a) function
* Added accessors to ANNarchy.core.Network to allow access to all populations/projections assigned to a Network
* Various bug fixes and improvements.

* ``pre_spike`` and ``post_spike`` fields of a spiking neuron can now modify pre and post synaptic variables::

pre_spike = """
g_target += w
post.nb_spikes += 1
"""

* ``SpikeSourceArray`` available on CUDA.
* ``Monitor.mean_fr()`` and ``Monitor.histogram()`` now work with PopulationViews (thanks ilysym).
* Many bug fixes with Python3 and CUDA.

* Rate-coded neurons can now use ``sum()`` to sum over all targets, instead of specifying them.
* ``Constant`` objects can now be created to define global-level parameters which do not need to be explicitly defined in Neurons/Synapses.
* Parameter definitions can use constants. Note that changing the constant after compilation does not change the parameter.
* The initial value of a variable (``init=``) can use constants instead of numerical values.
* ``report()`` has been improved and can now generate Markdown reports, which can be converted to html or pdf by pandoc.

* Issue 44: The performance of spiking networks with CUDA has been improved.
* ``Population.compute_firing_rate`` can now be called anytime to change the window over which the mean firing rate of a spiking neuron is computed.
* The performance of the exponential numerical method has been improved by computing the step size outside the loop (when possible).
* Mean-firing rate computation is now available for CUDA devices (slow!).
* Issue 43: the path to the CUDA installation can now be set in a config file at ``~/.config/ANNarchy/annarchy.json``.
* Simulations on GPU can be started on the command line by using ``--gpu`` or ``--gpu=2`` if you have multiple GPUs.