Initial podspec file

Created initial podspec file.
Did it as version 0.1, pointed to branch master and tested it and worked ok.

Now I think you should create a tag for Finch, adjust on source to point to that tag in order to remove the following warning:
```
- WARN  | Git sources should specify a tag.
```

I've pushed the podspec to my [Specs fork](https://github.com/marlonandrade/Specs) to test, but I wont open a pull request on CocoaPods/Specs, I'll wait for you to do so after final adjustments.

Btw, thanks for simplifying OpenAL with Finch =)

refs #34