NilClass implimented
Implimented Strings

Sapphire can now scan, parse and evailate string literals.  It can also
turn built-in types into strings with the to_s method.  The general method
for objects seems easier to write in sapphire after arrays and some other
primitive methods come about.  It will also take modules being availible
to easily impliment the to_s method for all builtins without needing to
rewrite the whole thing.

TODO:
 * Write general object to_s method
 * have repl use to_s
 * Modules needed to complete built-in classes
 * error messages
 * Bolean opperators
 * String parsing (still trying to figure out how this works)
 * Arrays and Hashes needed to make the string interface.