Tag to be used with the master branch of atlas/athena. Update(s) since 2.0.56: - atlas_add_test(...) now always runs the post-processing script (if one is defined), even if the test executable failed; - Updates to CheckerGccPlugins; - atlas_generate_cliddb(...) no longer generates/uses a dummy_clid.db file; - atlas_project(...) now only calls FindDoxygen.cmake if absolutely necessary; - Fixed the patching of Acts when building the project with Clang; - Added pyAMI to the list of modules built by the PyModules package; - Added the AthGenerationExternals project to the master branch; * Updated the build configurations of FastJet(Contrib) and HepMCAnalysis to accommodate the "new" project.