Start sddm.service after plymouth-quit.service

This will make sddm.service run after Plymouth, but upstream need to
be patch for retaining the splash.

See issue #196.
Don't reset background when starting the X server

See issue #196.
Merge pull request #198 from plfiorini/plymouth

Initial Plymouth support
Rename everything related to QAuth to something along the lines of SDDM::Auth
Fix typo
Merge pull request #201 from MartinBriza/qauth_rename

Rename everything related to QAuth to something along the lines of SDDM::Auth
Drop non-free font and use Oxygen

It was pointed out that Geosans Light is not a free font and that
causes licensing issues for distributions such as Fedora.

Remove the font and replace with Oxygen which would probably be
already installed by our users.

Closes #109
Merge pull request #204 from plfiorini/oxygenfont

Drop non-free font and use Oxygen
Initialize sigactions in signal handlers
Merge pull request #210 from MartinBriza/signals_initialize

Initialize sigactions in signal handlers
Remove unnecessary Session class from the daemon
Rewrote the config to a more rigid state

Resolves sddm/sddm#39

More configuration instances now available. Every instance is a separate class.

Sections are supported.

Serialization handled in a more sensitive way - does not remove comments.

Type handling is unified, using the QTextStream shift operators.

There are also some basic tests, to be further improved...

Probably the most overengineered configuration parser you've ever witnessed.
Move LastUser and LastSession into /var/lib/sddm/state.conf