Move price tag url generation JS from template to coffee/.js.
Move price tag event binding to coffee/.js.
Move adding new tags form template to coffee/.js.
Add functionality for delete all vendor items button.

- Moved kirppu/page to kirppu/vendor/items as it sort of made sense for the
  deleting and viewing all items to happen in the same url.
- Change default state for new items to be advertized instead of staged.
- Restrict deleting items to only those with state == Item.ADVERTIZED.

Conflicts:
	kirppu/app/views.py
Fix code style issues.
Add item creation with suffixes.

- More than one item can be added at once by giving a list of suffixes.
Restyle the price tag form.

- Use bootstrap styles because it's easy, although a bit verbose.
- Add option for tiny price tags.
- Add help text.
Show price tags from newest to oldest.
Add tiny price tags.
Implement 1px high PNGs and make PNGs default format.

- Added a custom writer based on the ImageWriter that renders the barcode
  as 1px high PNG. Size from 2000 bytes to 120 bytes.
- Also removes text from images and positions the html text below the barcode.
Fine tune price tag sizes for printing.

- Firefox seems to render the tags a bit bigger in print preview than chrome.
  This is solved by using percentage widths. It breaks landscape printing a
  bit but that shouldn't matter if portrait works.
Add missing for attributes to price tags form.
Make enable delete buttons affect the delete all button as well.
Fix PyCharm warnings.