D15070: Bindings: Support using sys paths for python install directory

[Stefan Brüns]

bruns marked 9 inline comments as done.

REPOSITORY
  R240 Extra CMake Modules

REVISION DETAIL
  https://phabricator.kde.org/D15070

To: bruns, #frameworks
Cc: cgiboudeaux, bcooksley, kde-frameworks-devel, kde-buildsystem, michaelh, 
ngraham, bruns