Use GNU install directories, and rpath

Use the GNU install directories, and ensure the install rpath is set to
match. Warning - the prefix directory will need to be removed as lib is
always found before any other location (with CMake 2.8.11.1 at least).

Change-Id: I03e8fcd4a18a20bf5f8723c971faa90b50d31dd9
Merge topic 'gnu-install-dirs' into master

bc8a55fe Use GNU install directories, and rpath