do not default to "paste.txt" as filename, but use <uuid>.txt (or .bin)
security fix: when showing potentially dangerous text/* types, emit them as text/plain (and turn the stupid browser sniffer off)
use werkzeug exception classes
load pygments css only on display view
reduce duplication in error templates
cleanup imports
fix pep8
if decoding text items with utf-8 fails, try with iso-8859-1
fix button rendering on display and item list view
use get-forms to make consistent styling simpler and avoid js hacks
add another btn-group container for list view
use submit always for the buttons
move hidden input field above submit button because otherwise the button is not rounded...
do not use submit button for delete, we want that js confirmation box...
put sha256 hexdigest into <code> element, so it will be monospace font
add input for the list item filename (when given, it won't use the uuid4 as filename)
if you upload a pdf on a windows (xp) system, you get application/x-pdf
add support for http basic auth request header - if header is present, use the password from there to determine permissions, fixes #69

$ curl -F 'file=@somefile;type=text/plain' http://user:password@localhost:5000/+upload   # works! ("user" is ignored)
compute permissions / logged_in status only once in before_request handler and put it into flask.g / flaskg
use a set for flaskg.permissions for simpler code / slightly better efficiency