Worked on polar charts. Connected line graphs across 0.
Some minor updates to polar charts
Added yAxis.gridLineInterpolation option with possible values "circle" or "polygon" for polar charts.
Made polar area charts null points or unconnected ends meet in center.
Implemented correct tooltip position for line type series in polar chart.
Various changes and improvements to polar charts
Merge remote-tracking branch 'origin/master' into radial

Conflicts:
	js/parts/MouseTracker.js
	js/parts/Series.js
Couple of improvements in polar charts
Fixed some issues in development of polar charts
Some more development on polar charts
--- Highstock 1.1.6 official release ---
Added AreaSplineRange and ColumnRange series types
used labels.overflow = 'justify' to prevent clipping of last label in demo
bar-basic.
Fixed regression issue with Axis.setTitle not destroying the old title before renewing. Closes #1039.
Merge remote-tracking branch 'origin/master'
Various fixes and improvements related to radial axes
Some fixes to gauges
Fixed JS error in Highstock with small chart. Closes #1040.
Various fixes and improvements for radial axes, gauges and polar charts.
Added better animation to polar charts. Created general wrap utility function to wrap an object method.