Set barcode as items id.

- Helps with debugging and should be useful in other ways too.
Set background color of printed tags to be different from normal tags.
Implement moving items to and from printed list.

- Items that are moved back from printed list automatically get a new barcode.
  The old item still exists but is hidden.
- Moving items back and forth is animated to try and help users see that
  something is going on.
Change price tag buttons into bootstrap glyphs.
Change wording of delete -> mark as printed.

- Don't disable mark as printed by default. It's not quite as severe as
  deleting.
- Change grouping of buttons in general and add a glyph to mark toggle.
Have move all to print button move items to printed list.

- Before they were just removed and only shown after reload.
- Change urls relating to move_all.
- Only set the printed property for items that havn't already been printed.
  Still takes too long though as django selects and saves the items one by
  one.