Mac: set policy to silent cmake >= 3.0 warnings

Set the following policies to "OLD" if cmake version is greater than
2.8.12:

CMP0026 - Disallow use of the LOCATION target property
CMP0045 - Error on non-existent target in get_target_property
build: cmake 3.1 compatibility

* fix problem with REMOVE_DUPLICATES on undefined lists
* since 3.1 file(GLOB FILEPATHS RELATIVE .. returns single / instead of // as
  previously - necessary adoptions for regex and matches done. Should
	work with all cmake versions.

Tested with 3.1.0-rc3
rdtk/shadow: install libraries versioned