IPython Notebook not respecting matplotlib's matplotlibrc axes background color setting

In my matplotlibrc file, I set a custom background color for axes (grey vs default white). I noticed awhile ago that when using the ipython notebook the background color for axes was no longer grey, but had reverted back to white. To make a long story short, I thought this was a matplotlib issue, so I didn't think anything of it. Well, tonight I looked into the issue and discovered that when creating a plot outside of the ipython notebook, the axes background is grey, but within the notebook the axes background is white.

If I manually set the axes background via rcParams, the correct background color is used.

I know this color issue occurs with commit ba9c97481eda20043bd5547563e00ff5c98773d1 (which I just tested), but I'm not sure when it was introduced.

```
{'commit_hash': u'ba9c974',
'commit_source': 'installation',
'default_encoding': 'UTF-8',
'ipython_path': '/usr/local/lib/python2.7/site-packages/IPython',
'ipython_version': '3.0.0-dev',
'os_name': 'posix',
'platform': 'Darwin-14.0.0-x86_64-i386-64bit',
'sys_executable': '/usr/local/opt/python/bin/python2.7',
'sys_platform': 'darwin',
'sys_version': '2.7.8 (default, Oct 19 2014, 16:02:00) \n[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.54)]'
}
```