Squashed commit of the following:

commit d3f63c62d9013d6fb8155194a6ae6caf17ec58b6
Author: stephane brossier <sbrossier@groupon.com>
Date:   Fri Sep 26 15:04:25 2014 -0700

    Minor renaming for usage api

commit f9c421c03d4caed7e75b835da18148c98db9ef66
Author: stephane brossier <sbrossier@groupon.com>
Date:   Fri Sep 26 14:17:45 2014 -0700

    Minor api renaming for usage

commit 53a85a143318d9b3f512a83d8747ffc4fd2122e3
Author: stephane brossier <stephane@ning.com>
Date:   Thu Sep 25 19:27:10 2014 -0700

    Update UsageApi to allow fetching and recording usage in bulk, and change granularity to be LocalDate

commit 8621ce380fc11227fb3db304b540b3628a56abf7
Author: stephane brossier <stephane@ning.com>
Date:   Mon Sep 22 18:09:36 2014 -0700

    Rework of the usage api (protoype for review)