Adding a new param to control Solr publication.

Bob H. has asked for Solr records from Tracksys to contain within
themselves some indication of their publication status.  We are going
to start flagging things as 'development', 'test' and 'production' and
he will update the relevant index accordingly.

This has not yet been tested.
Correcting syntax error.

This code was copied from the default transform,
which uses a $mode parameter not found here.

Deleting.
Merge branch 'issue-6a'