Alphabet range expansion in automata via a-z.A-Z.0-9

[Safwan Shaheer]

It would be nice to add an alphabet range expansion feature when defining the dfa

Some examples:-

1. A-D: ['A', 'B', 'C', 'D']
2. a-c,E-G: ['a', 'b', 'c', 'E', 'F', 'G']
3. 0-2: [0, 1, 2]
4. a-C: Throw an error as the highest we can go from a is z

[Safwan Shaheer]

Feature added in version 0.0.9