Merging over some uv editor tweaks from tuhopuu:

- Moved Weld/Align out of transform code, now it's a menu.
- Removed confirmation popups for LSCM unwrapping in the uv editor, didn't
  make sense anymore now we have undo.
- Extended select linked, to work more like it does in edit mode:
	- L: select linked uvs/faces under the mouse
	- Shift+L: select/deselect linked uvs/faces under the mouse
	(like shift+click for selecting single uvs/faces)
	- Ctrl+L: how L worked before
- More accurate uv selection: when selecting one uv from a group of uvs that
  are in the same position, it now selects the uv belonging to the face the
  mouse is over, instead of a random uv.
- 'View Selected' (numpad .-key) for both faceselect mode and the uv editor.

source/blender/include/BDR_editface.h

@@ -43,12 +43,12 @@ void default_tface(struct TFace *tface);
 void make_tfaces(struct Mesh *me);
 void reveal_tface(void);
 void hide_tface(void);
-void select_linked_tfaces(void);
+void select_linked_tfaces(int mode);
 void deselectall_tface(void);
 void selectswap_tface(void);
 void rotate_uv_tface(void);
 void minmax_tface(float *min, float *max);
-int face_pick(struct Mesh *me, short x, short y);
+int face_pick(struct Mesh *me, short x, short y, unsigned int *index);
 void face_select(void);
 void face_borderselect(void);
 float CalcNormUV(float *a, float *b, float *c);