Change hash_table lookups to use find instead of get to avoid potential task failure
and to remove the need for an array search for each symbol.

Add mut to local vars that I forgot to add last commit
Update README.md
Merge branch 'master' of github.com:kaseyc/Hephaestus
Basic NFA implementation
Finished NFA implementation.

Fixed syntax and logic errors in the previous commit (Now that I have access to a compiler again).
Added proper epsilon transitions.
Added Show trait
Updated main function with examples
Updated dfa.rs to handle changes to the Transition type.