Modified user agent for calls coming out of Sync Manager

App type will be NativeSmartSync or HybridSmartSync
(In line with the work we did in 2.0 for smartsync.js, the user agent for calls coming out of smartsync.js have HybridSmartSync or WebSmartSync as app type)
I suppose one way we could determine native vs. hybrid at runtime would be to reflect whether SFHybridViewController is available as a class in the app, somewhere in the initialization of `SalesforceSDKManager`.  Presumably, developers wouldn't go out of their way to add `SalesforceHybridSDK` to their apps unless they were creating a hybrid app.  Thoughts?