Turned on continuous integration testing

[schwern]

I've just turned on continuous integration testing via Travis CI. Didn't think anyone would mind.
https://travis-ci.org/schwern/method-signatures

The configuration can be edited in the .travis.yml file. I turned on every Perl they have. They don't have a 5.8 and it's only on Linux, but it's something!

Right now the emails go to me. It would be nice if failed builds went up as a Github issue or as comments on the appropriate existing issue (like if it sees a #123 in the commit message or the branch is issue/123). I'll leave that to somebody else.

I'm going to immediately close this. Just using the issue as a communication mechanism. Feel free to comment further and work on the config.