clean and rearrange platform/*/mvr.h

Created originally on Bitbucket by frantony (Antony Pavlov)

Was already merged in Bitbucket before import, marked as merged by the import user

Source changeset not longer availableat the time of import. Commit listwill look empty

To date the the platform/* directories contains a lot of duplicated code.

This commit series removes some code duplication from platform//mvr.h header files and demonstrates how we can move platform-independent declarations from platform//*.h to global header files.