Tagging the 1.0 branch with the following updates since 1.0.15: - Synchronised Eigen to build the same version (3.2.9) that's in LCG_88; - Included various CMake updates in AtlasLCG; - Added the PyAnalysis package, to provide NumPy for AnalysisBase; - Added DMTCP to the AthDerivation externals (to keep AthenaMP functional once the 21.0 updates get merged in); - Added BAT to the available externals, to be used by AnalysisBaseExternals. (AnalysisTop most of all.)