change ev argument name to tev in gesturedetector.lua

So people won't messed it up with ev in inputevet.lua
Merge pull request #738 from houqp/new_ui_houqp

change ev argument name to tev in gesturedetector.lua
bugfix: restore original zoom mode after cropping
Merge pull request #739 from chrox/new_ui_code

bugfix: restore original zoom mode after cropping