logging

Uses [RotatingFileHandler](https://docs.python.org/2/library/logging.handlers.html#rotatingfilehandler) so it will automatically start new files every mB.

Defaults to logging at `data.log`, but can be set with the `LOG` environment variable.

Logs currently look like:
```
datetime                    referrer    status   token        method  URI           time (microseconds)
----------------------------------------------------------------------------------------------------------
2014-04-06 04:25:35,438 	None      	200	integration_test	GET	/housing/rooms	19155
2014-04-06 04:25:35,459 	None      	200	integration_test	GET	/housing/rooms	17959
2014-04-06 04:25:35,486 	None      	200	integration_test	GET	/housing/rooms	21324
2014-04-06 04:25:35,510 	None      	200	integration_test	GET	/housing/rooms	18486
2014-04-06 04:25:35,532 	None      	200	integration_test	GET	/housing/rooms	18472
2014-04-06 04:25:35,557 	None      	200	integration_test	GET	/housing/rooms	21113
2014-04-06 04:25:35,564 	None      	429	integration_test	GET	/housing/rooms	982
2014-04-06 04:25:51,454 	None      	400	12345	GET	/housing/buildings/options/fake_attr	2479
2014-04-06 04:25:51,459 	None      	400	12345	GET	/housing/buildings/options/another_fake_attr	559
2014-04-06 04:25:51,464 	None      	200	12345	GET	/housing/buildings/options/building	1644
2014-04-06 04:25:51,469 	None      	401	NO_TOKEN	GET	/housing/buildings/options/building	208
2014-04-06 04:25:51,473 	None      	401	false	GET	/housing/buildings/options/building	337
2014-04-06 04:25:51,477 	None      	200	12345	GET	/housing/buildings/options/lounge	1204
2014-04-06 04:25:51,483 	None      	200	12345	GET	/housing/buildings/options/building	1588
2014-04-06 04:25:51,489 	None      	400	12345	GET	/housing/buildings/5	1594
2014-04-06 04:25:51,497 	None      	400	12345	GET	/housing/rooms/100	3952
2014-04-06 04:25:51,504 	None      	200	12345	GET	/housing/buildings	2390
2014-04-06 04:25:51,510 	None      	400	12345	GET	/housing/rooms/options/fake_attr	609
2014-04-06 04:25:51,513 	None      	400	12345	GET	/housing/rooms/options/another_fake_attr	686
2014-04-06 04:25:51,520 	None      	200	12345	GET	/housing/rooms/options/room_type	2028
2014-04-06 04:25:51,524 	None      	401	NO_TOKEN	GET	/housing/rooms/options/room_type	200
2014-04-06 04:25:51,528 	None      	401	false	GET	/housing/rooms/options/room_type	337
2014-04-06 04:25:51,533 	None      	200	12345	GET	/housing/rooms/options/room_type	1600
2014-04-06 04:25:51,538 	None      	200	12345	GET	/housing/rooms/options/room_type	1416
2014-04-06 04:25:51,545 	None      	400	12345	GET	/housing/rooms/5	1822
2014-04-06 04:25:51,552 	None      	400	12345	GET	/housing/rooms/100	2735
2014-04-06 04:25:51,565 	None      	200	12345	GET	/housing/rooms	8635
2014-04-06 04:25:51,690 	None      	200	integration_test	GET	/housing/rooms	20084
2014-04-06 04:25:51,713 	None      	200	integration_test	GET	/housing/rooms	19306
2014-04-06 04:25:51,735 	None      	200	integration_test	GET	/housing/rooms	17436
2014-04-06 04:25:51,757 	None      	200	integration_test	GET	/housing/rooms	18389
2014-04-06 04:25:51,779 	None      	200	integration_test	GET	/housing/rooms	17609
```

closes #94

Also suppressed logs during tests because the default output crowded the test results.