Call Taplytics async on `track` calls

[Ladan Nasserian]

To resolve @bbernberg deadlock issue:

Taplytics also dispatches to main thread synchronously within logEvent:value:metadata method. To resolve this, we will wrap track in

#define dispatch_main_async_safe(block)\
if ([NSThread isMainThread]) {\
    block();\
} else {\
    dispatch_async(dispatch_get_main_queue(), block);\
}