Fix string support methods to handle symbols too
More flexible configuration and bootstrapping

The process for initializing Bumbleworks has been more clearly
separated from bootstrapping the process definitions and participant
registration list, and both activities are now cleaned up
considerably.  Notably, none of the directories are required anymore;
if a default path doesn't exist, its associated behavior is a no-op.
For example, if no participant directory exists, no autoloading of
participants will occur.