Add some function to old style class

[Daetalus]

Note:

• The __complex__ could call complexNew in complex.cpp correctly. But complexNew need some improvements to support str and custom type.
• The behaviors of __unicode__, __get__, __set__, __delete__ are exact same as in CPython. IMHO, there is no need to write additional code in classobj.cpp.
• __missing__ only work in subclass of dict. So no need to write it in classobj.cpp.
• __coerce__ in old style class could call the new added coerce builtin function correctly. But the coerce need further improvements.

Update

• According import types; print sorted(types.InstanceType.__dict__.keys()) in CPython. Pyston has extra __base__.
• __doc__, __new__ seems as instance's class attributes in Pyston. If these three attribute were fine, then the old style class support was completed.
• __getslice__ and some other functions didn't change. Because if we copy instance_slice from CPython, then apply some change, it will very similar as the current one. But I will try to copy CPython code in next PR as much as possible.

[kmod]

Oh hmm you're right, there's no need to add a bunch of the ones that I had mentioned. I should have done this instead: import types; print sorted(types.InstanceType.__dict__.keys())

Looks like maybe we should remove these reversed, complex, enter, and exit, and add __index__. Sorry! Otherwise the change looks good.

[kmod]

Minor (not worth changing), but we could have directly copied CPython's instance_slice. It looks like the conversion got rid of some overhead, but I've been liking the approach of starting out with a 100% copy and then optimize as needed.

[kmod]

Awesome! Looks like we can now close #254 👍

fyi github doesn't send any notifications when you add new commits to a pull request, so if you leave a comment on it I will get back to you faster :)