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) and in small headings
* changed the way that frontends, NICs and HDDs are loaded. In this variant, everything that belongs to style issues is stored in an XML file, not in Java anymore.
* revamped "Profile edit" screen

also I changed library paths from Windows (`\`) to UNIX style (`/`) in `project.properties`. I hope this does not break anything...

and I added some English strings that are now used in the "Profile edit" screen. These are also already translated to German.