Changed settings signals to callbacks

Makes for more obvious settingshandling. The settings manager should
only be around to read the settings, not parse and shit.
Rewrote the config system, added manual options, changed config layout

Did a whole buncha things, yo.
Remade the theme system, now without custom css

Instead there's a json file with a few attributes that can be changed.
Merge branch 'revamped-config'

Conflicts:
	textarea.py
Made all settings print in lowercase