[Hawkular-dev] updated design doc for computing aggregate metrics

[John Sanda]

I have updated update the design doc[1] for aggregate metrics to include a brief summary of a few different approaches in terms of overall architecture. I have also included details on how work can be distributed and coordinated among instances of hawkular-metrics. The changes I am proposing will also have an impact on the REST API as has been discussed in some other recent threads. Thanks in advance for any feedback.

[1] http://bit.ly/1BAfF8d

- John