Added support for XLS

[cescp]

Based on xlrd, xlwt: http://www.python-excel.org/

[mjumbewu]

Ooh, @cescp I just saw this. Thanks! Lots of good stuff here. If you can, would you do me a favor and:

1. add xlrd==0.9.3 and xlwt==0.7.5 to the requirements.txt file (as they're now required for tests to pass), and
2. add a test (or more) for XLS parsing, maybe based off of tests.TestCSVParser.test_parse_two_lines_flat_csv. There's some refactoring that I'd like to do in the parsers and I want to make sure I wouldn't break what you've contributed.

[JocelynDelalande]

Please make it a different module, that's kinda bloating the lib with dependencies unrelated to CSV.

[danilke]

Hi, it will be so great if your it will have support for XLS!