Most changes in revision 55228 were reverted and Freestyle edge/face marks
were re-implemented using CD_ORIGINDEX layers of edge/poly custom data.
For this implementation to work properly, modifiers were updated so that
required CD_ORIGINDEX layers will be set. As pilot cases, the Mirror and
Solidify modifiers were updated (see comments in the code).
Some Freestyle-specific code is necessary in DerivedMesh.c so that the
CD_FREESTYLE_EDGE/FACE layers will be transferred from meshes to derived
meshes. This seems unnecessary, so further investigation is foreseen.