Removed debug prints, as we don't really need them now.
Fixed database updating from cache, until now only inserts was working
fine, updates failing. All because of forgotten comma :(.
Reworked handling of icons in servers lists, now they didn't
recreated, but reused from created on application start. Can also
save us much memory for long runs.
Moved gamemode detector to mainwindow_helpers, where it should be.
Refactored MainWindow source, splitted initialization and
helper functions into separate files.
Now lists headers sizes and positions are remembered and correctly
restored on launch.