added mock
removed commented out lines
Handle cases for partition with leader=-1 (not defined)
Merge branch 'master' into develop
check for broker None in send_broker_aware_request (added test for it)
Merge branch 'develop' into merge

Conflicts:
	test/test_unit.py
Changes based on comments by @rdiomar, plus added LeaderUnavailableError for clarity
clean up after comments from @rdiomar
Merge branch 'multihosts' into merge

Conflicts:
	test/test_unit.py
Merge branch 'develop' into merge

Conflicts:
	test/test_unit.py
fixed merge failures