Corrects dependency list (contained invalid pkgs)
Adds installation instructions for debian/ubuntu

For ubuntu/debian the instructions on how to install the server from repositories was missing.
owncloud -> ownCloud
Merge pull request #26 from RandolfCarter/LinuxInstall45

Corrects 4.5 Manual installation instructions & adds for Ubuntu/Debian
Add owncloud.com theme
Merge remote branch 'origin/stable45'

Conflicts:
	admin_manual/installation_source.rst