fix 207 by moving the set option into the header

This will fix (most of) #207 (closed) by moving the "set" option into the header and remove the bottom bar. I think we don't need a bin option here since "back" will do right that and act as cancel. Screenshot here:

I tried giving the header some transparency, but that would not be applied to the icons. Therefore I left the header as it is. This also ensures readability.

This will also fix #334 (closed) and will make !389 (closed) obsolete.