Fixes #39 : search and autocomplete are now case insensitive

Move filterTasks from controllers to todolib
Add unit testing on filters
Fixes #46 : Add shortcuts to change task's priority : + or > to increase
and - or < to decrease
Issue #46 : image for the new menu actions
Fixes #48 : Remove useless lines from Windows Packaging
Changed .gitignore to add swap files, backup files.
merged changes from upstream