Issue 163 - add field to configuration data indicating expected subject behavior for new streams

[FragLegs]

Addresses issue #163 by adding an optional field, default_subjects to the Transmitter Configuration data. The field is a string which can be either ALL or NONE and defaults to NONE if not provided. The interpretation of this field is as follows:

• ALL: All subjects are added by default. Calling remove_subject_endpoint acts like a filter, blocking the transmission of only the specified subjects. Calling add_subject_endpoint can effectively clear any filters set by remove_subject_endpoint but otherwise does nothing.
• NONE: No subjects are added by default. Calling add_subject_endpoint adds a subject to the stream. Calling remove_subject_endpoint can remove a previously added subject, but otherwise does nothing.

[timcappalli]

Deferring to @appsdesh on this one.

[tulshi]

Deferring to @appsdesh on this one.

@timcappalli You would need approve in order for us to be able to merge (or @iamseanodentity can)

[iamseanodentity]

I just caught up on the fireworks :)