Add READMEs for box and superformula
Improve geom/contour README
Improve bullet README
Sankey Plugin: Improved drawing of links

As seen in
http://bl.ocks.org/d/4599519/

using a thick line to draw links between blocks can lead to artifacts

this patch uses a set of 4 lines to draw the connection between blocks, see
http://bl.ocks.org/d/4599792/
Undefined local variable: 'radius'

Variable 'radius' inside hexagon() is undefined.
Based on changes previous commit it looks like this should be passed into hexagon().
RFC: An initial attempt at adding cycles and self-loops to sankeys
Correct typo
Change DAG/component layout
Update sankey/sankey.js
Add a reversible link
Link's value can be function

changed method value(link), added checking typeof link.value === 'function'
fixed bug in weightedTarget and weightedSource
fixed some typo
Merge remote-tracking branch 'remotes/tnightingale/patch-1'
Merge remote-tracking branch 'remotes/cmorse/master'

Conflicts:
	sankey/sankey.js
Merge remote-tracking branch 'remotes/artzub/master'
Merge remote-tracking branch 'remotes/kunalb/sankey'

Conflicts:
	sankey/sankey.js
Merge remote-tracking branch 'remotes/reidab/readme_improvement'

Conflicts:
	bullet/README.md
	geom/contour/README.md
created Makefile to produce production JS files, including a one-contains-all JS file carrying all plugins.