SpeedCrunch restores window to invalid position

[Felix Krull]

When restoring the SpeedCrunch main window, the application doesn't check if its saved window location is still valid; say, if the window was on a display that's disconnected or otherwise disabled, SpeedCrunch will restore its window to the now-invalid off-screen coordinates and the window will not be visible.

See https://groups.google.com/forum/#!topic/speedcrunch/MZLI0vweWUA

PR: https://bitbucket.org/heldercorreia/speedcrunch/pull-requests/16/use-qwidget-savegeometry-restoregeometry