Added tooltip to Score by Round chart.
Value spinner in open question dialog now get focus first.

Moved ancestor listener in Open Question Dialog to value spinner so it
gets focus first.
Implemented focus listener to Trivia Dialog Panel to listen for focus on
spinners and select all text.
Implemented creation of PNGs with charts by server for web publication.

Extracted all of the chart building to Factory methods in TriviaCharts
to allow the same code to be used by the GUI and to create PNGs.

Added the creation of chart PNGs to the server save routine. (Issue #33)