just compile ccap-numbering

it has not been done in a while
refactor labels and counters on pieces of content
add support for autogenerated xref link text
add footnotes and ToC links
pull out end-of-chapter/book solution numbering
remove unused mixins
Merge branch 'master' into refactor-numbering
change name of scope variable to part
changed eoc to end-part
remove default from .label() contexts
remove default from .counter() context
remove default from xref.content() context
remove unused mixins
Merge pull request #150 from Connexions/refactor-numbering

Refactor numbering merged to master.  Phil's test culminate in zero CSS changes/generated HTML changes