Scorep

There have been a lot of updates since the last release. However, the most important updates are:

* Support C backend for tracing
* Not enabled by default
* Only Python 3
* Huge reduction of instrumentation overhead
* Context managers can now be coupled with a User Region
* New test system (pytest)

The Score-P Python bindings do now support decorators to user Instrument functions. Together with the introduction of Decorators, some internal interfaces have been changed.

Other improvements are:
* The Instrumenter now remembers its initial state
* The LD_PRELOAD variable is emptied after Score-P is successfully initialised (Important if the python script starts another program)
* OPARI (OpenMP) compatibility was improved
* A fundamental performance benchmark was added
* Various bugfixes

This release is drafted due to the release of Score-P 6.0. It introduces the notion of `instrumenters`, which care about the interface between Score-P and Python. Different instrumenters are available. Other changes are:

* Introduce python context managers (used in the `with` statement) for user regions as well as enabling and disabling the instrumenter
* Use the sys.setprofile for the default instrumenter (should speed up the tracing)
* Allow to "unregister" the instrumenter to disable the recording of python calls (unregistering reduces the overhead)
* Add a dummy instrumenter (allows to leave user instrumentation in the code, even if no Score-P is loaded, it does nothing)
* Add rewind support
* Update the CI to bionic

The python bindings are now Python 2 complaint again. Moreover, a CI system with testing is now in place.

A lot has changed since the first Version. A few things are:
* use the Score-P `LD_PRELOAD` infrastructure
* allow the user to specify the Score-P flags to use
* the build, i.e. for `pip install` is simpler
* use only user instrumentation is possible again (by setting `--no-python`)
* grouping is now part of Score-P 5.0 and used to group modules
* ...