Adds initial podspec

DJProgressHUD_OSX doesn't have any version tags. I’ve added the current HEAD as version 0.0.1, but a version tag will make dependency resolution much easier.

[Semantic version](http://semver.org) tags (instead of plain commit hashes/revisions) allow for [resolution of cross-dependencies](https://github.com/CocoaPods/Specs/wiki/Cross-dependencies-resolution-example).

If you're unsure of how to create a tag; you can tag the current HEAD as, for instance, version 1.0.0, like this:

```
$ git tag -a 1.0.0 -m "Tag release 1.0.0"
$ git push --tags
```

Once you've pushed a tag, the podspec line:
````s.source       = { :git => "https://github.com/danielmj/DJProgressHUD_OSX.git", :commit => "988334280ea95a5ef2640deebab5663b5fb24f7f" }````

Will need to be changed to:
````s.source       = { :git => "https://github.com/danielmj/DJProgressHUD_OSX.git", :tag => "1.0.0" }````