Restore default safe_mode argument in markdown_to_plain_text
Transplant another XSS fix from hhu-theme
See https://github.com/hhucn/adhocracy.hhu_theme/issues/125 for details
Remove iframe border

Due to the restricted user html handling in
dfa8f5e3c10f00e28af1adede2054d8d0a1cbbe9, the non-html5-compliant
`frameborder="0"` attribute, which is part of the default youtube and
other embed codes, isn't permitted by the lxml html cleaner.

Therefore iframe borders are now hidden in the default css, as nobody
wants that anyway.
Helper function to determine whether HTML is allowed
Only show HTML notice if HTML is allowed
Fix DetachedInstanceError after StatusCodeRedirect

In certain cases, e.g. after an exception has been thrown, the database
session may be detached, but database objects managed by the orm are
still refered to from the same thread.

Such objects can be merged with the new db session, as described in
http://stackoverflow.com/a/9705458/201743

This is done with `c.user` which is re-retrieved from repoze.who after a
StatusCodeRedirect.

This fixes what ade22d799ebe894b1f7a9fbc3a5685e6aceca4e7 works around.

See also discussion on: https://bitbucket.org/phihag/hhu-
adhocracy/issue/168/error-handler-causes-is-not-bound-to-a
Avoid UnmappedInstanceError if c.user is None

Addendum to afa02732f672af01ef33dbaa1520beabdf577256
Fix many cancel urls for relative_urls case

Also, use some more useful cancel urls where appropriate.
Test that the markdown version in use is safe
Remove stray diff
(Ported 40e3c6bbeb99bc1a1772d82859d244cc2af8fc14 from adhocracy.hhu_theme)
pep8 / pyflakes

Make most files compliant with newest versions of pep8 (1.4.1) and
pyflakes (0.6.1), using flake8 and vim-flake8
Merge branch 'develop' of ssh://github.com/liqd/adhocracy into develop
Remove fanstatic_url helper
Surprisingly, removing this chunk of code has no effect. I could not find any usage of fanstatic_url, tests pass, and everything looks as before
Remove commented-out block of code
Ignore temporary journal files
Construct fanstatic base url like any other base URL (Closes adhocracy.hhu_theme#100 )
Merge pull request #207 from phihag/remove_fanstatic_urlhelper

Remove fanstatic_url helper
Upgrade SQLAlchemy (0.7.9 -> 0.7.10)
Use secure login cookies on SSL connections (fixes #210, part 1)
Strip dash from frontpage title (Port of https://github.com/hhucn/adhocracy.hhu_theme/issues/117 )