Combine leader PCRE patterns into single pattern with optional groups

Allows all paragraph classes to have same credit hour (or span)
detection.
Remove summary attribute from major description table for validation

Already covered by caption element.
Adjust course scanning pattern with word boundary and negative lookahead

The word boundary is a better than keeping track of each character used
to terminate a course sequence. The negative lookahead prevents matching
body copy following a course that starts with numbers (ex
19<sup>th</sup>)
Updating bulletin section.
Merge pull request #679 from unl-creq/request-7369

Finalize Request #7369
Add tests for EPUB leader injection and condensed course number seq
Merge pull request #678 from kabel/majordesc-tweeks

Addressing Judy's concerns from July 25