- Canvas: added per-item context menus
- Isocurve: 
     option to extend curves to array boundaries
     option to generate QPainterPath instead of vertex array
- Isosurface is a bajillion times faster
- ViewBox
     added clear() method
     added locate(item) method (shows where an item is for debugging)

Bugfixes:
- automated example testing working properly
- Exporter gets incorrect source rect when operating on PlotWidget
- Set correct DPI and size for SVG exporter
- GLMeshItem works properly with whole-mesh color specified as sequence
- bugfix in functions.transformCoordinates for rotated matrices
- reload library checks for modules that are imported multiple times
- GraphicsObject, UIGraphicsItem: added workaround for PyQt / itemChange bug
- ScatterPlotItem: disable cached render during export

Other:
- added documentation for several functions
- minor updates to setup.py