#16 refactor SocialClient

[Allen Lee]

Changing SocialClient - instead of containing all of the specific know-how
regarding specific social experiments (groupsum, musical choice, puzzle,
lagrange, etc.) it should use an ExperimentFactory that returns the
appropriate SumExperiment, MusicalChoiceExperiment, etc., that
contains:

1. DebriefingPanel
2. GamePanel
3. InstructionPanel

and has a handle(SocialEvent) method used to perform custom event
handling and processing to modify the state of each of these panels.