remove onGesture method overload in BBoxWidget

since ges pos can be acqured by the second argument
move toggleswitch into separate widget file

also remove onGesture method reload in ToggleSwitch widget
update config.lua after moving toggleswitch to separate file
add math.lua, move all math related helpers in to it
Merge pull request #755 from houqp/new_ui_fix

some code clean up