Remove spines and ticks in rcParams

Hello there,
I started working on this PR to make my [`prettyplotlib`](https://github.com/olgabot/prettyplotlib) library obsolete by allowing you to do everything via rcParams.

So far I've only gotten the `spines` to work: http://nbviewer.ipython.org/gist/olgabot/8260601

Current todos are:

1. `set_ticks_location` via rcParams
2. Tell `scatter` to `get_current_color_cycle` for the `facecolor`. Ditto for `fill_between` and `fill_betweenx`
3. Set `boxplot` colors and lines: https://github.com/olgabot/prettyplotlib/wiki/Examples-with-code#boxplot
4. Add `image.cmap_divergent` for data with both negative and positive values in a heatmap
5. (maybe) allow for only y- or x-axis grids, e.g. for bar plots and histograms https://github.com/olgabot/prettyplotlib/wiki/Examples-with-code#bar-with-a-white-grid-to-erase-and-yet-add-information

Thoughts? Does this look like it's going in the right direction?