Enable python syntax highlighting on README

[jacobh]

note: Github isn't rendering the python syntax highlighting here, so this will only work once github fixes something on their end.

[dfunckt]

Seems like the correct identifier for code-block is "pycon". See raw source of redis-py readme.

Thanks!

[jacobh]

I think that's got it. let me know if you would like this to be rebased together

[dfunckt]

Yes, that would be great, thanks.

[dfunckt]

Apparently, pycon is for Python console code, python for plain Python code. Github seems to choke on html+django, so I removed it.

I have applied your commits to a temporary branch that I plan to merge to master later on, so no need to squash your commits.

[dfunckt]

Merged in 8677cd3. Thanks!