Replace ${PROJECT_NAME} and @PROJECT_NAME@ by OCE in all CMake files

OCCT developers generate their CMake files from WOK files, so
they won't use our files.
Write all CMake command names in lowercase
Cosmetics: Make whitespace more consistent
Fix typo

Thanks to tpaviot.
Merge pull request #392 from tpaviot/review/cmake-coding-style

Make CMake files more readable