Fix for theme colors not correctly applied to the user interface.

This commit partly reverts the changes in revision 53197 for
making Freestyle optional.  Specifically #ifdef WITH_FREESTYLE
was removed from source/blender/editors/include/UI_resources.h so
that Freestyle-related theme properties are always defined
regardless of whether Freestyle is enabled or not.  This is in
line with the fact that Freestyle-related DNA components are
always defined no matter how a build is configured.

source/blender/editors/include/UI_resources.h

@@ -200,10 +200,10 @@ enum {
 	TH_STITCH_PREVIEW_UNSTITCHABLE,
 	TH_STITCH_PREVIEW_ACTIVE,
 
-#ifdef WITH_FREESTYLE
+/* #ifdef WITH_FREESTYLE */
 	TH_FREESTYLE_EDGE_MARK,
 	TH_FREESTYLE_FACE_MARK,
-#endif
+/* #endif */
 
 	TH_MATCH,           /* highlight color for search matches */
 	TH_SELECT_HIGHLIGHT, /* highlight color for selected outliner item */