Add right-click menu items for marking/unmarking as draft.
Only show the appropriate menu items for unmarking/marking as draft.
When "publishing a post" set the publish date to now.
Write the date to the JSON as a ISO 8601 compliant string.
Remove the published time from the post if it's a draft.
Update Default.tribo to new directory structure.

Also adds metadata file.
Show the date in the UI.
Move text label color changing on selection into code.

Having two instances of each label in IB was making things hard to do as
far as aligning text. Everything still works the same though.
When clicking on an empty row, don't crash when showing the menu.
Show drafts in preview mode, but don't include for publishing.

Changes process and write post methods to include a parameter on whether
or not to include drafts.
Document new code.