tei header popup

[jchartrand]

Create a popup that can be invoked from two places:

the TEIHeader element in the structure view.
a new button that appears up in the top right of the editor, labelled Edit Header

In fact the TEIHeader element in the structure view should, when clicked, only open the popup. That particular element should have no other menu options, including no right click menu.

The popup itself should show the elements in the header as a form. This is an first pass at the header so include those elements that seem obvious, and list in an email those about which you are unsure.

[ajmacdonald]

Done, although saving isn't supported yet.