Upgrade to Mono 3.2.5 on Travis.

    Per [1] it's easier to do this if we ask Travis to run on a Mac host.

    1: http://stackoverflow.com/questions/16751772/how-do-i-use-travis-ci-with-c-sharp-or-f/16751773#16751773
Merge pull request #190 from Pash-Project/Travis-Mac5

Upgrade to Mono 3.2.5 on Travis.