Dosvidanya, old compositor!

You served well and now desired retirement, but you'll always live in our hearts.

And for sure -- monument!

       +-------------------------------------------+
      /   ++==+   .  ..   .   ...    .  ..     .  /
     /   //    ++==++  ++  ++     ++==++ ++==++  /
    /   //    //  //  //\\//\\   //  // //  //  /
   /   ++==+ ++==++  //      \\ //==++ ++==++  /
  /  .    ...   ..    .       //  ..  ...     /
 +-------------------------------------------+

Some notes:
- Removed all code which was from inside ifdef WITH_COMPOSITOR_LEGACY
- Removed some functions which were used by old compositor only but
  weren't ported to new color management
- Removed WITH_COMPOSITOR_LEGACY from build systems
- node_composite_util.h was in fatc used by compo nodes specification
  files, so added it back to cmake.

  Could be cleaned up by moving header files to files where they're
  actually needed but would consider this is a separate task.

- Should be no functional changes!

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53787 954f8c5b-7b00-dc11-b283-0030488c597c