Write test and fix lib install issue

[st0012]

I think test this by retap/reinstall it every time is not a very smart practice, especially for the copying lib part (I think it still has some issue for now).
So I suggest writing some tests for it, and it seems that we can test it on Travis CI by using its OSX build environment
@adlerhsieh Can you give it a try when you have time?

[adlerhsieh]

Yeap, sure. Can give it a try.

[st0012]

@adlerhsieh I think we can improve/test this formula like what golang does: https://github.com/Homebrew/homebrew-core/blob/master/Formula/go.rb

[adlerhsieh]

Cool. Thanks for the reference.