New features and bug fixes

• Added inset for legend.position option - #326
• Added pie.sort and donut.sort option - #328
• Added category and categories API - #327
• Added bar.zerobased option - #333
• Added area.zerobased option - #360
• Modified to use chart object as this in event handlers - #327
• Modified option for focus grid line - #307
• Fixed regions and date handling - #343
• Fixed bug for y domain - #317
• Fixed bug for unsorted timeseries data - #322
• Fixed bug for timeseries data input - #311
• Fixed stacking line with 0 value - #316
• Fixed loading json with undefined data - #325
• Fixed y domain padding when label shown - #317
• Fixed bar chart bars moving on color update - #329
• Fixed to update left padding automatically - #295
• Fixed legend position when element appended - #334
• Fixed zoom and redraw on category axis
• Fixed initial drawing - #309 #336
• Fixed data.colors API to be able to access default colors - #341
• Fixed load API to accept unload without input - #342
• Fixed to accept 0 of padding option - #361