added AsLong class to String
Merge pull request #52 from To1ne/String_AsLong

added AsLong class to String
String_AsLong might throw an exception when conversion fails
Merge pull request #54 from To1ne/String_AsLong

String_AsLong might throw an exception when conversion fails
Remove String AsLong Behaviour
Switched `New` interface to use size function. Hid some implementations.