genn-team/genn: Service release 2.2.2

Release Notes for GeNN v2.2.2 This release includes minor new features and several bug fixes for certain system configurations. User Side Changes Added support for the new version (2.0) of the Brian simulation package for Python. Added a mechanism for setting user-defined flags for the C++ compiler and NVCC compiler, via GENN_PREFERENCES. Bug fixes: Fixed a problem with atomicAdd() redefinitions on certain CUDA runtime versions and GPU configurations. Fixed an incorrect bracket placement bug in code generation for certain models. Fixed an incorrect neuron group indexing bug in the learning kernel, for certain models. The dry-run compile phase now stores temporary files in the current directory, rather than the temp directory, solving issues o\ n some systems. The LINK_FLAGS and INCLUDE_FLAGS in the common windows makefile include 'makefile_commin_win.mk' are now appended to, rathe\ r than being overwritten, fixing issues with custom user makefiles on Windows. NB: If you are migrating from release 2.1 or earlier please refer to the release notes for Release 2.2 and 2.2.1 as there are a number of alterations you will need to implement for the migration. Please refer to the full documentation for further details, tutorials and complete code documentation