[Owncloud] ownCloud bugfix release

[Robin Appelman]

Hi,

I just backported a number of bugfixes to the stable branch.
I suggest releasing a bugfix release for ownCloud 2 soon.

The backported fixes include
- upgrade to sabredav 1.5.4 to solve caldav issues with evolution
- various fixes for caldav support
- improved mimetype detection
- various visual fixes
- improved pgsql support
- partial workaround for *dav on apache+php-cgi

And various other minor fixes.

-- 
- Robin Appelman