Produce shorter output on no arguments

This is accompanying pull request for RFE: http://www.cmake.org/Bug/view.php?id=14973

Instead printing complete help cmake/ccmake now prints only Usage section and
extra information how to get more help or start your build.

Implementation Details:

  Usage help type was renamed to Help, and new Usage was introduces that prints
  only command line usage information without any extra details.

  Commands add some extra information when no arguments are passed.