The free select tool now commits on double click inside a closed
polygon, which caused the foreground select tool to switch modes in
the middle of a click, breaking both its own and its parent class'
state.

Fixed by detecting whether the commit was done by double click and
delaying the mode switch until after the parent class button release
code is done.

Unrelated: Don't call both COMMIT and HALT, the generic tool mechanism
does that automatically now, forgot to port this file.