Installing large directories, e.g., the output of a doxygen run, prints
one line per file resulting in too much noise in the build output. Add
an option to the install(DIRECTORY) command to not print anything upon
make install.
Extend the RunCMake.install test with cases covering MESSAGE_NEVER
behavior of the install(DIRECTORY) command.
Suggested-by: Stefan Eilemann <Stefan.Eilemann@epfl.ch>
Brad King