add background hinting in koptinterface
disable hinting temporarily in config dialog and flipping mode and cropping dialog
Since hinting is of little use in these situations.
Merge pull request #787 from chrox/background_hint

add background hinting in koptinterface
Merge pull request #789 from chrox/new_ui_code

dismiss chrome bar before launching the reader
listen home key press in filechooser
Merge pull request #790 from houqp/new_ui_fix

listen home key press in filechooser
rearranged source tree
Merge pull request #791 from houqp/new_ui_houqp

rearrange source tree
bugfix: require button widget