add macros cmake_print_properties() and cmake_print_variables()

This patch adds the file CMakePrintHelpers.cmake, which provides
the macros (functions) cmake_print_properties() and cmake_print_variables(),
which are useful e.g. for debugging and make inspecting target (or other)
properties easier.

Alex
Merge topic 'PrintHelperFunctions' into next

e32ff96 add macros cmake_print_properties() and cmake_print_variables()