Added improved default value dimension to SheetLayer
Points and PointPlot now support points with magnitude (colored by cmap)
Improved support of Nx3 arrays in Points constructor
Bug fixes and improvements in clarity
Generalized the constructor of Points, removing 'magnitudes' argument

This constructor is both simpler and more flexible. Furthermore, exactly
the same constructor can be used for VectorFields.
Introduced VectorField as a subclass of Points
Initial commit of VectorFieldPlot with incomplete update_frame method
Enabled animating colors and angles on Quiver plots
Docstring fixes to US English spelling of 'color'
Added range property to Points for obtaining magnitude range
Added range_column property to VectorField to pick column used by range
Added control for color limits in PointPlot via normalize_individually
Docstring improvement
Added color limit control to VectorFieldPlot via normalize_individually
Made the relative arrow length the first extra dimension by default
Initial commit of the new vectorfield ViewOperation