Removed Ubuntu 11.10 and added 13.10 as supported versions.

Writing this from a 13.10 machine I just built code on, so we know it works. 11.10 is EOL as of May of last year - we can expect it to break on new machines.

Actually the reason I installed 13.10 here is that 12.04 won't work without serious messing around under the hood on Haswell Macbooks (all the new ones). So we need to think about deprecating that too when 14.04 comes out.