change from using raw metlog method call to using the metlog-raven
method
issue 1 - updated docs to indicate that the SENTRY_DSN must be
speicified or else sentry may reject messages if your project id is
not 1
bumped dependency on metlog-raven to 0.4
raven no longer support django < 1.4
bumped to version 0.2 as we are migrating from a raw metlog() call to
using the metlog-raven plugin
Merge pull request #2 from mozilla-services/vng/issue_1

Vng/issue 1