Merge pull request #435 from DavidSouther/development

Added Fn::bind polyfill.
Added renderWatch to stackedAreaChart.
Fleshing out renderWatch for discreteBarChart.
Fleshing out renderWatch for multiBarHorizontalChart.
Fleshing out renderWatch for stackedAreaChart.
Fleshing out renderWatch for pieChart.
feature: refactored state management into nv.utils object; implemented in legend and multibarchart
ignore bower