CHOP-661: Add information to try to zero in on remaining failures.

Make testrunner.py module interpret $INTEGRATION_TEST_VERBOSE environment
variable, setting module global VERBOSE. Enable/disable debug() output based
on that variable, defaulting to VERBOSE True. Add debug() output to
freeport(), including reporting exceptions.
Add debug() output to test_llsdmessage_peer.py, including normal
BaseHTTPRequestHandler output: when VERBOSE is set, don't suppress
log_request() or log_error() output.
Add C++ verbose() function to query $INTEGRATION_TEST_VERBOSE, broken out as
two functions so we only have to interpret the value once. Default to 'true'.
Move C++ commtest_data::getport(variable) function to global namespace, broken
out as two functions to cache the value. Report value received when verbose()
returns true.