Merge pull request #43 from bepetersn/master

fix some subtle tarbell things, make the "edit this text" thing spiffier
Update getting started instructions

Update the getting started instructions in the README.

I got Tarbell and this site up and running today and updated the
README to reflect things that could be more clear and linked to
portions of the Tarbell docs where appropriate.

I also removed the ``sudo`` from the ``pip`` command to install
Tarbell as you shouldn't need to use sudo when installing into a
virtualenv.
Community Area map

Implement scaffolding of Leaflet-based map of Chicago Community
Areas.

Add GeoJSON file of Community Area geographies, population and
some conviction counts.

Implement Backbone models and collections that handle GeoJSON.

Add Jasmine-based tests for Backbone code.

Add a stylesheet, viz.css for styles related to visualization
elements.

Add new stylesheet, dependencies and initialization JavaScript
to index.html.

Update .gitignore so git ignores vim swap files.

Addresses https://github.com/sc3/cook-convictions/issues/48
Make Community Area map a choropleth

Update Community Area GeoJSON so it includes number of convictions
and convictions per-capita.

Add view options to configure choropleth "bins".

Add view for legend.

Addresses https://github.com/sc3/cook-convictions/issues/48
Refactor choropleth bins

Wrap data structures of bins that shade the map features and draw
the legend in classes to hide implementation details from code
that uses them.

Addresses https://github.com/sc3/cook-convictions/issues/48
Basic d3 bar chart

Add a basic, reusable d3 chart function and use it to draw a
chart for convictions by category.

This could use some refinement in terms of colors and axis styles,
but it does provide a reasonable framework for drawing bar charts
and a namespace and reference implementation for drawing other
kinds of charts.

This implementation is based on the patterns described in these
articles:

* http://bost.ocks.org/mike/bar/3/
* http://bost.ocks.org/mike/chart/
* http://blog.apps.npr.org/2014/05/19/responsive-charts.html
Horizontal bar chart

Extend the barChart function to add some additional hooks for
customization, allowing us to implement a horizontal bar chart.
Merge pull request #56 from sc3/viz_js

Add per-capita convictions choropleth and basic bar chart