ENH: Turn off CPACK_BINARY_TBZ2 and CPACK_BINARY_ZIP by default. Strictly speaking, this changes behavior from cpack 2.6, but now that cpack returns a non-zero exit code when it encounters an error, and it is an error to try to use a generator that is not available... It makes sense to turn these off by default since not everybody has these generators installed. It is easy for a project to turn these options back on if they need to: simply set(CPACK_BINARY_TBZ2 ON) or set(CPACK_BINARY_ZIP ON) before include(CPack) in your CMakeLists.txt...
