which essentially means some cleanup and no more regressions:

- add state POINT_BOTH for moving the entire line
- use the move cursor for moving the entire line
- reorder some functions
- set the tool to handle click events
- make clicks and no-motion releases behave properly
- #if 0 the code for "shapeburst handles", they don't work yet
- return to gimp:shapeburst until we have figured progress for GEGL ops
- indentation, stuff...