remove debug
upgrade interact, simplify drag.cljs
implement clear API
configure drop-off: revert or trash
spare pieces WIP
Merge branch 'master' of github.com:ornicar/chessground

* 'master' of github.com:ornicar/chessground:
  Allow reselect of same color
  Don't select non-movable piece
  Fix activation and deactivation of draggable state
  Update mobile-dev example

Conflicts:
	src/chessground/drag.cljs
disable spare piece example