updated readme
Documentation and algorithm written

The documentation for hashpass is completely written, as is the Python implementation.

TODO:
- Testing:
  - Absolutely no testing has been done yet, and no test cases have been written
  - The code has only been run under python 2.7 on OS X Mountain Lion
  - A reference implementation in a second programming language should be made to shake out any python-specific bugs
- User interface
  - A CLI is definitely going to be written, a GUI may be written as well
- Python 3.3 support forthcoming
  - The only change I can see offhand is defining basestring and long