compile using the same version of less

instead of the system version
removing an old piece of stylesheet which was styled to the content of the Precalculus Chapter 2 collection, which is outdated.
fixes for answer key, QA feature text and top page margins
clean up of mathML testing section, exercise testing and various testing fluff code
various fixes of github issues (#361, #360, #359, #356, #265, #264
fixes for equation numbering, try-it header space, top page space reduction and misc fixes
adjustment of top and bottom page margins to accomodate custom introductions
updating figure alignment constraints for 150dpi imagery
Merge pull request #369 from Connexions/precalc-sectionexercises

cleaning up .section[title="Section Exercises"]
Merge pull request #352 from Connexions/same-less

compile using the same version of less
left align review questions, removal of pipe from chapter number and titles in page header
Fixes various github issues dated 3/10
Merge pull request #370 from Connexions/psychology-github-issues

various fixes of github issues (#361, #360, #359, #356, #265, #264
Turning off end of book references, various github issue fixes
adding economics and psychology css files
Merge branch 'master' of https://github.com/Connexions/oer.exports
fix of conflicts in history and merge with updated master
Merge pull request #373 from Connexions/precalculus-bugfixes

PreCalculus bugfixes for miscellaneous layout issues, figures, page margins and spacing
Merge pull request #375 from Connexions/stacey-history-fixes

History Bugfixes - (stacey)
Merging master