Switching sidemenu to use bootstrap's built-in "affix" class for fixed position.
Merge branch 'master' of https://github.com/SaltTechnology/SaltTechnology.github.io

Conflicts:
	_layouts/default.html
Updated rest of pages to use affix sidebar modification
Merge branch 'master' of https://github.com/SaltTechnology/SaltTechnology.github.io