Mouse hover event is SLOW! As a result, prop "want_hover" is default setted to "0", means disabled.

We will add additional plugin function to reset this prop in future.

2. sloved a tiny problem that selection  box's coord will be mis-calculated during rotating.

We gives every geo_graphics_item an prop, which is a boolean variable. Items can be selected by mouse dragging.

try to partical slove ui deadlock in heavy items count , however, we need a abstract view in low level 0~3.

2.make a copy painting , sloved +180 -180 polygon drawing problem.