Implement back tracking (Recursion)

[matthewdeanmartin]

When a sub part has realized that we have misread a sentence, it should modify it, and kick it back to the very top, i.e. call SentenceFactory()

Would need to track

• Original input
• Determine which part of input needs to be changed (i.e. this is not a number)
• Track # of back tracks and prevent infinite back tracking.

May want to implement memoizing at the same time. (BUT ONLY IF IT IS REALLY EASY)