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removing an old piece of stylesheet which was styled to the content of the Precalculus Chapter 2 collection, which is outdated.
various fixes of github issues (#361, #360, #359, #356, #265, #264
Reducing space between abstract data list items in chapter outlines
Removing any space possible in the chapter outlines
Greatly reducing margin between all list items.
Returning a bit of margin to list items. Fixing a bug relating to the last list item in a parent element.
Merge pull request #374 from Connexions/physics-github-issues

Physics github issues Refs #371, #372
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
Merge pull request #370 from Connexions/psychology-github-issues

various fixes of github issues (#361, #360, #359, #356, #265, #264
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