KDC++ Code

The users that cannot be interacted with are now marked in the list
(showing them using italics).
Also, some refactoring is done to how the IPs and ports are handled.

Refactoring: removed the useless settings-related methods from the
Application class.

Minor fix; the unknown user flags are now handled properly.

Loading of the user icons is optimized; Qt no longer spams the error
messages about not loading an SVG file.
Strange thing found: some users have unknown flags like 33 or 57, or
other crazy numbers.

Lots of changes, but nothing works still.
Both active and passive connections now work but very unstable.

Everything is borken! The idea is to have a single accepting socket in
the application object, so all incoming connections would be accepted
there and then moved to the transfers.

The transfer list now displays states of transfers.

The file list now marks ourselves.

The default download location can now be configured via the preferences
dialog.
The additional download location can now be chosen directly in the file
list.

Seems like the users are now added and removed properly!