Remove Pods directory from .gitignore

Committing the Pods directory of the demo project seems to be a more sane default.
The demo project should be able to build right after checkout without the need to run `pod install` or even installing CocoaPods.
If the library author doesn't like to commit the Pods directory he can still add it to the local .gitignore or it's already in the global gitignore.
Merge pull request #23 from toco/master

Remove Pods directory from .gitignore