Update Mono version & cleans up and aggregates fixes #279 and #278

Aside from changing the Travis config file, this incorporates the
fix from @dsyme (#279) and then it makes the documentation tests
pass - not quite sure why this works though (see #280).
Force loading of FSharp.Data to fix docs on Mono
Merge pull request #282 from tpetricek/master

Update Mono version & cleans up and aggregates fixes #279 and #278