[Owncloud] Bookmarks App

[blizzz at arthur-schiwon.de]

Hey, 

i commited that app yesterday evening, as you may have seen. Of course it
is not yet complete and needs some polishing. 

For instance, it does not seem to work with sqlite, yet, as it was
reported. I have a look into it tonight, from what i already saw it is not
a big issue, presumably :)

Besides a note: there is a known bug, that bookmarks saved without tag do
not show up. 
And: seperate multiple tags with blank spaces.

Cheers
Arthur