Genome::Processes can run and be viewed

No schema changes this time.
Genome::Processes are now ready to be used (for example in VariantReporting).
I try to avoid die $self->error_message, because the error_message gets printed out unconditionally.  So, for instance, if we wrap the method in a try - catch and successfully handle the error, we still see the error_message.  I think it is misleading to see error messages that we've handled.