Rollbar

New features:

- For Tornado requests, gather the request start time. See [33](https://github.com/rollbar/pyrollbar/pull/33)
- Add handler which uses Tornado's `AsyncHTTPClient`. To use this, set your 'handler' to 'tornado'. See [34](https://github.com/rollbar/pyrollbar/pull/34)

- Improvements to RollbarHandler logging handler. It now:
- extracts more information out of each record (i.e. metadata like pathname and creation time)
- uses the format string, with arguments not yet replaced, as the main message body. This will result in much better grouping in Rollbar.

Note about upgrading from 0.8.x: unless you are using RollbarHandler, there are no breaking changes. If you are using RolbarHandler, then this will change the way your data appears in Rollbar (to the better, in our opinion).

- Provide a way to blocklist types from being repr()'d while gathering local variables.

- Fix uncaught ImproperlyConfigured exception when importing Rollbar in a Django REST Framework environment without a settings module loaded ([28](https://github.com/rollbar/pyrollbar/pull/28))

- Only attempt local variable extraction if traceback frames are of the correct type, print a warning otherwise
- Fix JSON request param extraction for Werkzeug requests (Pyramid, Flask, etc)

- Local variables collection now enabled by default.
- Fixed scrubbing for utf8 param names.