DataSet: play and invalidation are only relevant if we streamDataFromModel
DataSet: Add ability to manually add a new row of points

appendStaticDataPoint acts just like appendDataPoint, in that data of
the same format is appended to _dataSeriesArry and the same SAMPLE_ADDED
event is dispatched, but it uses data passed in without trying to
get model properties.

[#63473964]
DataSet: Add loadDataSet and serialize functions

These move data in and out in exactly the same format as the
dataSet's internal _dataSeriesArry. It's possible that we may wish
to modify this so that the data is easier to parse by humans.

loadDataSet iterates through the data and calls appendStaticDataPoint
repeatedly for each row, allowing components that listen to SAMPLE_ADDED
to behave as if new data were coming in. We may want a quicker version
that just makes a direct copy of the array.

[#63473964]
Load and serialize table data using DataSet. BREAKS any authored tables.

Update radioactivity-graph example to demonstrate new table authoring.

[#63473964]