UI changes

* moved "About" and "Check connection" from navigation drawer to the actionbar (but never shown as action)
* added padding on many places
* changed font in statusbar (that shows profile and connection status)
* changed font in  small headings (on "Profile edit", "Device info" and "Currently playing" screens)
* changed the way that frontends, NICs and HDDs are loaded. Now, everything that belongs to style is stored in XML files, Java is not involved anymore.
* revamped "Profile edit" screen

I added some English strings that are now used in the "Profile edit" screen. These are also already translated to German.

I also changed the library paths from Windows (`\`) to UNIX style (`/`) in `project.properties`. I hope this does not break anything... But otherwise, I had not been able to build it myself because I'm working in a Linux environment.