Add default return value for application willFinishLaunchingWithOptions

The return value is necessary to be able to use openURL because this callback is only called if willFinishLaunchingWithOptions and didFinishLaunchingWithOptions return true. See: http://goo.gl/Q0OQBF
Merge pull request #397 from tma/patch-1

Add default return value for application willFinishLaunchingWithOptions
update the deprecated presentModalViewController:animated: in favor of the new presentViewController:animated:completion: and updated tests
Merge pull request #404 from MarkVillacampa/update-present-view-controller

substitute deprecated presentModalViewController:animated: for presentViewController:animated:completion:
Add Gem Version and Dependency Status badges to README
Merge pull request #406 from ryanlntn/feature/add-badges

Add Gem Version and Dependency Status badges to README
Resolve Gemfile conflicts