Added boolean switch so that RunProgress display can be disabled
Renamed 'enabled' switch to 'display' and moved to ProgressBar class
ProgressBar.display now selects between different display modes
Added broadcast option to ProgressBar and new RemoteProgress class

These options may it possible to view progress even when stdout is not
displayed directly. For instance, this may be used to view the progress
of non-interactive or batch jobs.
Fixed NdIndexableMapping data_type check error message
Fixed bug in ScatterPlot, not allowing display of unstacked View
Enabled overlaying of DataLayers and Annotations
Enabled overlaying of DataGrid objects
A sliced SheetView now inherits the value dimension
Fixed index handling in DFrame conversion method
Added support for spline Annotations
Split plots module into plotting subpackage
Fixed ScatterPlot constructor