separate pythonClassName from pythonFunction

[koka831]

Ref: #18
This is the enhancement to separate classname from function name.
about regexp of pythonClassName, I intend to make it compliant with pep.

[nfnty]

Thanks, waiting for the improved regex.

[koka831]

now I created g:python_highlight_class_names highlight option, which is enable by default.
and add some testcases to make sure class name starts with Capital.
review me again, please.

[terminalnode]

Layman here so I don't think I'm qualified to leave an actual review, but I tried this and it works well for me.

I changed the color to Special because that works better in my theme, but everything seems to work as expected.

[richin13]

Works great, @nfnty any specific reason to not merge this?

[koka831]

@nfnty may I ask you, what do you mean by

the improved regex

If this PR don't work as expected, I'll fix it.

[ckudera]

Any updates on this PR? Works fine for me.

[nfnty]

Thanks!