Adding Travis config and shell scripts to build wheels.

@silvolu Please take a look.

Notice I added a `## When will a new build occur` section to the README since you last reviewed.
Good call.

I put them at the top so people would know what to change if they wanted to do the same thing for other projects.

I also see that I stupidly (d'oh) left my hacks in there to make Travis run on my own fork.