Pedantic tidy up of CMakeLists

"dbr/Ben" <b...@...>

Boring changes \o/

Add Boost 1.44 and 1.45 to additional versions list (1.45 works fine, can't imagine 1.44 is incompatible)

Move the find OpenGL/OIIO stuff into OCIOMacros. Probably belongs in a Find___.cmake file

Try and find OIIO/OpenGL/etc, build applications if they are found

Components more consistently check if their requirements are met in the root CMakeLists.txt, rather than wrapping the components CMakeList in an if() statement. This makes it easy to see what components have requirements by looking at one file

Tidier and hopefully more helpful messages regarding applications and their requirements