Gave MainWindow control over all keypress events

This allows MainWindow to filter through for events that should apply
everywhere. Glade was grabbing Up and Down. This returns control to
scroll through the worksheet. Fixes bug #74.
Gave control back to selections
Merge branch 'master' into addpoppler
Gave control to text editor
Merge branch 'master' into addpoppler
Merge branch 'addpoppler' into glib_new