fixes for statistics appendix text to allow for multiple appendices with subsections
refactor code to target docbook generated tags with only display:none + additional code work for toc and header padding
Merge pull request #147 from Connexions/stats-appendix-fix

Creation of code to support multiple appendices for Statistics text.
removal of important property from styles in precalc less file
Small cleanup changes, whitespace etc
Merge remote-tracking branch 'origin/precalculus-cleanup' into refactor-precalculus
Precalculus template refactoring