Rigify:

- Added two driven-shape-key rig types that create and drive shape keys on a mesh/meshes based on the distance or rotation difference between two bones.
- Fixed bug in finger curl rig type where secondary finger controls were not created.  Finger type can also now (optionally) have a hinge switch (useful when using it for wings).
- Changed the blending system in rigify_utils to use copy_transforms constraints instead of copy_loc+copy_rot.
- Finished the quadruped leg type.  Now has both ik and fk control and ik/fk switching.  Also uses a rotating bone to control the knee direction instead of a pole target (seems to work more consistently for quadruped setups).  There's still one annoying bug regarding foot roll, but it's not blocking.  I'll track it down later.
- Mouth rig now creates corrective shape keys on the face mesh for dealing with mouth corners when they spread open.
- Biped arm and leg types now cause mesh to scale when you scale the fk controls.
- Misc improvements to the rig types.

release/scripts/modules/rigify/arm_biped.py

@@ -223,6 +223,7 @@ def fk(obj, definitions, base_names, options):
     fk_chain.forearm_p.rotation_mode = 'XYZ'
     fk_chain.forearm_p.lock_rotation = (False, True, True)
     fk_chain.hand_p.rotation_mode = 'ZXY'
+    fk_chain.arm_p.lock_location = True, True, True
 
     con = fk_chain.arm_p.constraints.new('COPY_LOCATION')
     con.target = obj
@@ -276,7 +277,14 @@ def fk(obj, definitions, base_names, options):
     fk_chain.arm_b.layer     = layer
     fk_chain.forearm_b.layer = layer
     fk_chain.hand_b.layer    = layer
-
+    
+    # Forearm was getting wrong roll somehow.  Hack to fix that.
+    bpy.ops.object.mode_set(mode='EDIT')
+    fk_chain.update()
+    mt.update()
+    fk_chain.forearm_e.roll = mt.forearm_e.roll
+    bpy.ops.object.mode_set(mode='OBJECT')
+    
     bpy.ops.object.mode_set(mode='EDIT')
     return None, fk_chain.arm, fk_chain.forearm, fk_chain.hand
 
@@ -338,6 +346,11 @@ def deform(obj, definitions, base_names, options):
     con.target = obj
     con.subtarget = definitions[2]
     
+    con = uarm1.constraints.new('COPY_SCALE')
+    con.name = "trackto"
+    con.target = obj
+    con.subtarget = definitions[1]
+    
     con = uarm2.constraints.new('COPY_ROTATION')
     con.name = "copy_rot"
     con.target = obj
@@ -349,6 +362,11 @@ def deform(obj, definitions, base_names, options):
     con.target = obj
     con.subtarget = definitions[2]
     
+    con = farm1.constraints.new('COPY_SCALE')
+    con.name = "copy_rot"
+    con.target = obj
+    con.subtarget = definitions[2]
+    
     con = farm2.constraints.new('COPY_ROTATION')
     con.name = "copy_rot"
     con.target = obj