Add support for section wrappers on the single template

If any class names are entered for section wrapper, a DIV element
with these class names is created as a wrapper for the section
being output in the template.
Add section-wrapper to remaining admin and front end templates

This allows for an arbitrary list of classes to be entered. If
found, then a DIV element is output as a wrapper around the current
SECTION element
Merge pull request #56 from washingtonstateuniversity/builder/wrap-divs

[PR] Allow for entry of arbitrary class names to create DIV wrapper around sections