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.
The CTest version control refactoring broke the value returned for the
ctest_update command's RETURN_VALUE argument. The value is supposed to
be the number of files updated, but the refactoring accidentally made it
the number of locally modified files after the update.
This corrects the terse documentation and adds detail to the full
documentation of some commands. It also normalizes the layout of the
documentation string endings to make adding lines easier.