Seam Cutting in Faceselect Mode:

- Mark Border Seam: mark edges on the border of face selection as seam.
- Clear Seam: clears seams in selected faces.
Hotkey: Ctrl+E

- Alt+RMB Click: mark/clear edge as seam
- Alt+Shift+RMB Click: mark/clear seams along the shortest/straightest path
  from last marked seam. The cost of the path also includes some measure of
  'straightness' next to the typical distance to make things work more
  predicatble and edgeloop friendly. Note that this cuts a path from edge to
  edge, not vertex to vertex. That gives some nice control over the direction
  of the seam.

Also includes:

- Removed old LSCM code.
- Fix updates glitches with DerivedMesh/Subsurf drawing in FaceSelect mode.
  Now there's a drawMappedFacesTex instead of drawFacesTex.
- Minimize Stretch menu entry called Limit Stitch.
- Removed the lasttface global, was being set before it was used anyway, so
  might as wel return from a function.
- Moved some backbuf sampling code to drawview.c from editmesh, so it can be
  used by Faceselect and VPaint.
- Use BLI_heap in parametrizer.c.

source/blender/include/BDR_unwrapper.h

@@ -36,8 +36,7 @@
 void set_seamtface(void); /* set TF_SEAM flags in tfaces */
 void select_linked_tfaces_with_seams(int mode, Mesh *me, unsigned int index);
 
-void unwrap_lscm(void); /* unwrap faces selected in 3d view */
-void unwrap_lscm_new(void);
+void unwrap_lscm(short seamcut); /* unwrap faces selected in 3d view */
 void minimize_stretch_tface_uv(void); /* optimize faces selected in uv editor */
 void smooth_area_tface_uv(void);