fixed capitalizing bug #35

Fixes capitalized as follows:
- all lowercase --> all lowercase with replacement
- all upper --> all upper with replacement
- mixed format --> prints original word, no replacement
Check the "check caps" block I added below. 

istitle() and isupper() are disjoint events (I tested this). So in the block below, you only don't want to replace the word if (1) it failed both those checks and (2) it is not fully lowercase. So you don't need to check islower() in every case, only in cases where you're not istitle() or isupper().