update nvd3, additional chart config options
move nv.d3.css to lib folder
fix css location
docs in chart models
fix pie chart bug in nvd3
Merge branch 'master' into nvd3

Conflicts:
	corehq/apps/reports/commtrack/standard.py
minor tweaks
update nvd3 lib
Merge branch 'master' into nvd3
move nvd3 css back
move nvd3 css back
Merge pull request #524 from dimagi/nvd3

nvd3 update