Blender Git Loki

GPencil: Added operator to allow directly clicking on strokes to select them and their points

* D RMB = Select the stroke point under the cursor
* D Shift RMB = Select the stroke point udner the cursor, while retaining existing selection
* D W = Select whole stroke

As a result of these changes, the eraser has had to be moved to another binding,
i.e. D X. This doesn't really work that great since it starts working immediately.