Entity status + drafty

Same changes as https://www.drupal.org/node/2389185
When removing the entity handlers, cps_override_changeset() can no longer only take effect on the handlers - because the handlers don't exist any more as a separate thing.

That left the choice of having two API functions - one that gets the global changeset without overrides, and one with overrides, or just alway using cps_get_current_changeset() everywhere. I personally found the distinction between the two very confusing when first debugging issues on CPS, so consolidating seemed more predictable.

getCurrentChangeset() was treating the published changeset as FALSE, so when consolidating the override into cps_get_current_changeset() the least-disruptive change was to have the published changeset == FALSE - then if (cps_get_current_changeset()) still works as a check - otherwise we'd always need to compare against the constant.