Update Page.register_extension example in docs
Docs update - display full module path for extensions

Shorthands were deprecated in FeinCMS 1.6 and removed in FeinCMS 1.8
Merge pull request #517 from bmihelac/patch-9

Update Page.register_extension example in docs
Merge pull request #518 from bmihelac/patch-10

Docs update - display full module path for extensions
Prevent a crash in feincms_nav by returning early when page is None
Merge branch 'master' into next

* master:
  Docs update - display full module path for extensions
  Update Page.register_extension example in docs
Fix #522: django.contrib.markup has been deprecated

No strong preference for markdown, it's just that I remember the syntax :-)
More copy-pasting
Update docs to mention modeladmins
Merge pull request #523 from sunliwen/master

Update docs to mention modeladmins
Fix all flake8 2.1.0 warnings
Fix all flake8 2.1.0 warnings

Conflicts:
	feincms/__init__.py
Merge branch 'master' into next

* master:
  Fix all flake8 2.1.0 warnings
Merge remote-tracking branch 'official/master'

* official/master:
  Update docs to mention modeladmins
Merge branch 'master' into next

* master:
  Update docs to mention modeladmins
Merge remote-tracking branch 'frog32/next' into next

* frog32/next:
  always test with the latest patch release
don't use _meta.get_field_by_name in register_templates because this doesn't work until app registry is fully populated