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.
Merge pull request #5 from danpalmer/master

Tweaks