Add en_GB locale for d3.time.format.
Merge pull request #761 from jasondavies/time-en_GB

Add en_GB locale for d3.time.format.
Automate d3.time.format locale generation.

This avoids having to include a large number of locales in the D3
repository, and also reduces the potential for typos when transcribing
locale mappings.
Add format-locale.js dependency to Makefile.
Simplify.
Improve handling of intermediate locale files.
Update to UglifyJS v1.3.3.

Also, update node-canvas to v0.13.0 for better compatibility with
Node.js v0.8.x.
d3.format: support locales.

Note: the previous commit broke some tests relating to locale date
parsing, due to expecting "%m/%d/%y". On my system, the "en_US" locale
uses "%m/%d/%Y" by default. I've updated the tests to use %Y.
Fix dangling globals.
d3.format: fix decimal points for null grouping.
d3.format: Always apply locale decimal point.

It should be applied even when no grouping is used. Thanks, @mbostock!
Simplify.
Add d3.geo.path.bounds.

This computes the bounding box for a given GeoJSON object using the
current projection.
Simplify d3.geo.bounds implementation.

Also, add rudimentary test.
Rename d3_path_circle for consistency.

I guess this may end up in d3.svg at some point, but consistency is
good!
d3.format: support align and non-decimal formats.

This also fixes a minor discrepancy with Python's implementation:
format("013,d")(-42000000) now returns "-0,042,000,000" instead of
"-042,000,000".
d3.format: support center-align.
d3.format: support negative zeroes.
Fix #771 for singleton ordinal domains.
Minor optimisation.