Improves Graphite time range handling

Graphite has extremely flexible (almost natural language like) date-time
range support.

This commit adds in 99.9% of the functionality (all except for the
strptime style format as I couldn't quite work out what that would
look like)

Also changes the url to use from/target instead of from/to to remain
consistent with Graphite.
wip initial clock support
wip - rough and ready overall tooltips
Wip - Clock chartled, heavily based on the the rather awesome dashing framework.
WiP Adding Graphite summarize function