Tag to be used with the master branch of atlas/athena. Update(s) since 2.0.40: - Taught AtlasLCG how to find system-installed python modules correctly; - Added fixes for the optional installation of components in projects. (To make the installation succeed even if the build didn't.) - Now using FindPython and FindPython2 for finding python in all projects; - Added Python3 compatibility fixes to the Gdb and PyModules packages and to AtlasLCG modules; - Added an option for atlas_install_python_modules(...) not to fail on syntax errors in the installed files.