Pre-merger changes.

Deprecated Freestyle-specific elements were removed from the code base,
in order to address all comments from branch code reviews.
https://codereview.appspot.com/7416049/

Backward compatibility won't be maintained in the following components:

- Freestyle edge/face marks in old .blend files are ignored.

Old .blend files can be converted by loading and saving the files using
a Freestyle branch build between revision 55581 and 55842.

- External style modules are no longer supported.

Instead text datablocks must be used to keep style module files within
.blend files.  A branch build between revision 55741 and 55842 is useful
for identifying the style module file names that need reconfiguring.