* Replacing FIR_SWIFT_NAME macro with NS_SWIFT_NAME.
This pushes the minimum Xcode version to 7.3, as NS_SWIFT_NAME was
limited before that version (which is why the macro was introduced in
the first place).
* Fixed FIRMessaging header
* Enumerator using generic. Cleaner for .. in .. loop in Swift
So
for childSnapshot in snapshot.children {
you don't need to cast each child. Each cild is already known as DataSnapshot
* Update FIRDataSnapshot.h
* Update FIRMutableData.h
* Update FIRMutableData.m