code fix on operators and draw cam handler

2.0.5

- changed: redo panel for GP layer picker has better name and display active layer name
- changed: some operator id_name to expose "add shortcut" in context menu for some button
- fixed: error with draw_cam handler when no camera is active

handler_draw_cam.py

@@ -34,7 +34,7 @@ def draw_cam_frame_callback_2d():
     context = bpy.context
     if context.region_data.view_perspective != 'CAMERA':
         return
-    if context.scene.camera.name != 'draw_cam':
+    if not context.scene.camera or context.scene.camera.name != 'draw_cam':
         return
 
     main_cam = context.scene.camera.parent