stub the lynx Timer object when metrics are disabled

Fixes trello#38.
add a few more API functions, resp. stubs

...to reduce noise in the ERROR logs on PROD systems
Merge pull request #44 from yelworc/trello#35_apistubs

add a few more API functions, resp. stubs
Merge pull request #43 from yelworc/trello#38

stub the lynx Timer object when metrics are disabled