Make hashid.py usable as a python module

Move argparse configuration and input processing into a `main()` function.

Example Usage:
```
In [1]: import hashid

In [2]: list(hashid.identifyHash('d41d8cd98f00b204e9800998ecf8427e'))
Out[2]: 
[('MD5', '0'),
 ('MD4', '900'),
 ('MD2', False),
 ('Double MD5', '2600'),
 ('LM', '3000'),
 ('RAdmin v2.x', False),
 ('RIPEMD-128', False),
 ('Haval-128', False),
 ('Tiger-128', False),
 ('Snefru-128', False),
 ('ZipMonster', False),
 ('Skein-256(128)', False),
 ('Skein-512(128)', False),
 ('Lotus Notes/Domino 5', '8600'),
 ('NTLM', '1000'),
 ('Domain Cached Credentials', '1100'),
 ('mscash', '1100'),
 ('Domain Cached Credentials 2', '2100'),
 ('mscash2', '2100'),
 ('DNSSEC(NSEC3)', '8300')]
```