console_encode() fails on unicode when using ipython-notebook
When running in ipnb (linux) I get:

> > > pandas.common.console_encode(u"\u05d0")
> > > '?'

I traced this back to sys.stdin.encoding being set to None rather then 'utf-8' like in the shell.

Attached is a fix for your consideration. the test is just a stub since mocking is required
to reproduce the bug when testing in the shell instead of inside ipnb.
