Add translation section to README
Updated README to be more specific
Improve explanation of delta gauges
Use backquotes for the "foo" examples
Explain about Coda Timers
Overview of Librato metrics used and also how to reduce the volume of
reported metrics
Support for new metrics translation && tests.
Assume previous value to be zero for delta gauges
Initialize the delta tracker with initial counts
Merge pull request #44 from librato/feature/translation

Add better doco and support for delta tracking.