Add Travis CI support

[zcsizmadia]

It will add support for Travis CI. If there is a pull request to the repo, Travis CI will automatically build the library for Linux x86/x64 and OSX x86/x64, so you can see before the merge if the change will break anything.

You must create a Silicondust account on Travis, and enable libhdhomerun.

Check out my Travis CI auto build results and Readme.md badge on my fork:

https://github.com/zcsizmadia/libhdhomerun https://travis-ci.org/zcsizmadia/libhdhomerun