Unify the TinyMCE editor so that all options are on all instances

This is the first step in widening each area so that columns are
not squeezed together.
Expand each column to fill section in page builder, add counter text
Add a future toggle to each column in a section for collapsing
Setup a toggle switch on individual columns within sections
Introduce a single columns view for admin area

Detect the type of section being used and apply the number of
columns dynamically rather than having a layout for each number
of columns
Remove old admin layouts specific to column numbers
Change wsuwp-spine-halves-column to wsuwp-spine-builder-column

Allows more generic targetting without the addition of yet another
class
Allow for persistence of column visibility state
Reorganize JS for click event on handlediv
Toggle the display of the toggle handle on open close of columns
Back up a bit on the click event to watch toggles on new sections
Add an image to represent thirds
Merge pull request #126 from washingtonstateuniversity/unify-editor

[PR] Improve column editor experience in the Builder template