Modify SettingsActivity design

Right now I decided to go with my own custom design for the
SettingsActivity instead of going for PreferenceActivity as that will take
too much time. PreferenceActivity will be implemented in next versions.

- add separators
- format the budget correctly
- modify the layout to look neatly
Add layouts for different screen densities

Even though the layout was scaling fine I decided to not risk and added
the layout to folders for different screen densities.

- add layouts for different screen densities