App Installation Failed: Implements Workaround

#### What does it do?

This workaround forces the Xcode build process to re-sign the Today extension. This, in turn, fixes the "App Installation Failed" error we've been seeing around

More details [here](https://github.com/CocoaPods/CocoaPods/issues/790) and [here](http://stackoverflow.com/questions/2157964/receive-message-a-signed-resource-has-been-added-modified-or-deleted-when-tr/2207055#comment24259784_2207055)

Closes #2917


**Note:** This is **just** a workaround. 

/cc @astralbodies + @sendhil