Indicate Here/Away presence when viewing query/PM

Discussion

Quasseldroid should show some sort of "Here/Away" presence indication when viewing a query/private message. This would make it easier to tell if the person you're talking to has gone away in the middle of writing a long message, etc.

Ideas

• A green circle/yellow triangle/gray X/whatever somewhere near the buffer name
  • Mimics Quassel desktop
  • Should follow Material design/icons
• Italicize the buffer name for users that are away
  • Might be easier and more obvious, but might not look nice - not sure
• Something else..?