Fix #51 and remove load method referenced from objc files

[kealdishx]

In objc file, I use __attribute__((constructor)) to replace +load method. The calling sequence is load -> constructor -> main at runtime.

In swift file, The solution is that get all classes that conformed to SelfAware protocol via runtime and call functions defined in SelfAware protocol before applicationDidFinishLaunching method called.And I use static let instance to do the same thing as dispatch_once.

[Coeur]

Woah, you're good, I didn't know about __attribute__((constructor)) before.

[pmusolino]

Thanks for this PR @iiiCeBlink! I will review it asap.