[beeswax] Support Spark SQL table metadata format

It is slightly different than HiveServer2.
[search] Make timeline support timestamps with milliseconds
HUE-2494 [search] Timeline remove doesn't delete the chart

Checked for a non null object on KO
[oozie] Order coordinator actions on the Oozie side

https://github.com/cloudera/hue/pull/132

Oozie configuration can have 'oozie.coord.actions.default.length' parameter which overloads oozie 'len'
param, and Hue may not display latest coordinator actions if they are exceeding this value.
Since https://issues.apache.org/jira/browse/OOZIE-1754 oozie can sort coordinator actions.
We need to request oozie to sort coordinator actions in descending order and display them
correctly by dashboard.py.
[doc] Update Hue screenshot
[core] Add ConditionalGetMiddleware

This middleware adds Content-Length to the response, and
adds ETag awareness, which we can eventually use to allow
the browser to cache pages.
[core] Remove trailing whitespace