[Owncloud] Performance improvements

[Bart Visscher]

Hello all,

Just a quick report about the performance improvements i did.
Doing a directory listing of a directory with 1000 files took almost 1
second on my machine. The fixes that are now in stable4 almost halfs
that time. Using the fscache and doing smarter lookup for extra webdav
properties, the request only takes about 0.3 seconds. And this should
also scale much better.

Bart