Current chapter identification attributes (add chapter@sid,eid)

Proposal

Require a new pair of attributes for the <chapter> element to be used for unambiguously identifying the start and end location for a chapter.
- Add the attribute sid for identifying the chapter start location
- Add the attribute eid for identifying the chapter end location

Background

USX 3.0 adds a pair of attributes to <verse> (sid and eid) (see #34) which are used to unambiguously identify the start and end position for scripture verse text within the scripture discourse structure. This is a companion pair of attributes for <chapter>.

In USX 3.0 a <chapter/> milestone is required at the start and at the end of the verse text, with corresponding sid and eid attributes. In previous versions of USX, only a <chapter/> start milestone was required.

Example

Genesis 2:23-25

<chapter number="1" style="c" sid="GEN 1" />
  <para style="s">The Story of Creation</para>
  <para style="p">
    <verse number="1" style="v" sid="GEN 1:1" />In the beginning, when God created the universe, 
...
    <verse number="31" style="v" sid="GEN 1:31" />God looked at everything he had made, 
      and he was very pleased. Evening passed and morning came—that was the sixth day.
    <verse eid="GEN 1:31" />
  </para>
<chapter eid="GEN 1" />
<chapter number="2" style="c" sid="GEN 2" />

ubsicap / usx