allow setting limit units as a TimeUnit (which is what setup_limits command does)
dump_limits: support printing limits to stdout
accept TimeUnits for both unit and unit_value setters.  Test this functionality
pep8, grammar
pep8
add test to verify dump_limits to stdout
cleanup; adjust mocking
Merge pull request #10 from aaltepet/master

Correct bug preventing setup_limits from loading new limits; allow dump_limits to dump to stdout.