This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.
This creates command mode add_test(NAME ...). This signature is
extensible with more keyword arguments later. The main purpose is to
enable automatic replacement of target names with built target file
locations. A side effect of this feature is support for tests that only
run under specific configurations.