Implement SBL style table of contents

This will be a lot of work.
  - the \section* commands will need to be modified to add lines to the table of contents
  - the commands associated with outputting the table of contents will need to be modified

Also:
  - We may need to reconsider using \part as the first level heading because:
    - standard LaTeX documents will normally assume that \section is the first level
    - the title page will not work well if a document does not include the first level heading (\part at present)
    - my recommendation would be to use \section through \subparagraph for all the SBL heading styles and leave \part unimplemented for the time being (Pete will want to speak into this though)