Term proposal system: Icons and Shortcuts for Editing

For editing proposals:

• Use only icons and shortcuts, not clicks "somewhere" (e.g. in the headline for opening the editor, or general blur for saving).
  + re-implemented: clicking anywhere else starts the saving-process (incl. closing the current editor, updating buttons etc)
• When editing-component is opened: allow shortcuts for save (CTRL+S) and for cancel (ESCAPE).
• In headlines:
  • remove ":"
  • move edit/save/cancel-icons: place them right after the content