API now uses Class methods.
Using a static C array of ints for the charsets.
Pre-split the common words into it's array of components.
Use the built in `-[NSArray containsObject:]` as this will probably be a cleverer implementation than makes sense to put into this class.
Spit API into 2 methods. One that uses GCD designed for UI work, and one that doesn't and therefore allows the developer tighter control over how it works.

Added brief documentation to the header file.