[Owncloud] owncloud download level of entry: tar.bz -> zip

[Pascal d'Hermilly]

I was a bit supprised to see that the official download of OC5 is in TAR BZIP format since Owncloud has always tried to keep a low level of entry for new deployments.
This means an extra obstacle for many people running windows, (mac also?)
If the download was in zip this obstacle would not be present.
The compression ratio is a little lower.
not compressed=43,7 MB
Tar.bz=13,2 MB
Zip=17,8 MB

I think tar.bz gives some head aches to some people that we can avoid by using zip.

Just a heads up.