in common error

* IOS: Added identification for which action was taken in case there was many

* Changed the action identifier key to _actionIdentifier

* attempt to fix installation with cocoapods

* Remove unnecessary header imports

Error:

```
Assertion failure in -[GIPReachability startWithCompletionHandler:]
'NSInternalInconsistencyException', reason: 'GIPReachability should be used from the main thread'
```

Fixes #233

clear badge for ios 9 when clearing all notifications

* Update RNFIRMessaging.h

* Update RNFIRMesssaging.m

In conforming with the method signatures as is the case with the
android version, I limited the arguments for `send()` to just
`senderId` and `payload`. This can still be improved upon by adding
`sendDataMessageSuccess` and `sendDataMessageFailure` to events being
fired across the bridge to Js.

* Add firestack header search paths

If users have installed firestack, modules may live here instead.
Include them just in case.

* Include firestack paths to frameworks

* Import Firebase via module

* Ignore xcuserdata