Adding event time / interval

[berryma4]

I've added a validity interval to log entries in the service.
A log has two extra fields; eventStart, eventEnd
And there are two new URL params:
history=audit -> audit trace of all changes
history=event -> event trace over time (ie. 6am started pump down, 8am at vacuum )
history=& -> defaults to audit for compat

sort=created
sort=modified
sort=eventStart

For the time being, we should implement just the event instant, so people can just say when something happened, and sort on it.

Then, we need to think more on what this looks like and the use cases.

[berryma4]

made branch eventTest_issue_27 for testing

[berryma4]

@AnthonyDionise can you fork the eventTest_issue_27 branch and work on this.

[tonystonee]

Yes I can !