- perform scanning in a thread
- change the label of the scan button
- trigger cancel with the same button and with the ESC key
- process all GUI updates in asynchronous mode.
Do not use a top window as parent of popups:
- If a top window goes away in an application with multiple instances of
XInsaneWidget, any call to a scanner widget leads to a crash.
Minor changes.
4b23b1f3de