Expose parse_client_transport_line() and parse_server_transport_line() for the test suite
Add some mocks needed to unit test ClientTransportPlugin/ServerTransportPlugin config line parsing
Add unit test for ClientTransportPlugin/ServerTransportPlugin config line parsing
Replace all calls to parse_client_transport_line() or parse_server_transport_line() with new parse_transport_line() stub
Merge and refactor redundant parse_client_transport_line() and parse_server_transport_line() functions
Merge remote-tracking branch 'andrea/ticket6456'

Somewhat tricky conflicts:
	src/or/config.c

Also, s/test_assert/tt_assert in test_config.c
Fix unused-argument warnings
Fix a wide line I introduced
Changes file for Andrea's work on 6456