Slight improvements on the download page, FAQ, misc

The checksums are not interesting to most people so I made them smaller. Is there a cleaner way to do it?

SHA1 is broken and as slow as SHA256 so i removed it. MD5 is broken though at least faster but i think if anyone cares enough to check the sums, he'll want a secure one so this just makes us look like we don't care.

Removed 2 more FAQs which only make sense to people coming from Nexuiz.

Moved some stuff to HTTPS.

Fixed social links on cacs page (reddit was missing).