progress on creating an observer role in approval groups.
removing debugging code.
code and tests for the 'observer' role in approval groups.
[Finishes #77388246] Remove the Cartmaker panel if it already exists
[Finishes #77388190] Change text on 'keep shopping' button
removing extraneous comment.
Merge pull request #36 from annalee/observers

"observer" role in approval groups
Added architecture walkthrough doc
[Finishes #77415234] Display sub-total for each cart item
[#77415234] Updated templates to use sub-totals
Merge pull request #38 from 18F/77388190_change_keep_shopping

[Finishes #77388190] Change text on 'keep shopping' button
Merge pull request #37 from 18F/77388246_fix_multiple_screens

[Finishes #77388246] Remove the Cartmaker panel if it already exists
Merge pull request #39 from 18F/77415234_cart_item_subtotals

77415234 cart item subtotals
Add .map files to quiet error messages
New table and panel formatting for cartmaker.
finish conforming to @JTag's sketches.
Merge branch 'freeform_cart_v4' of https://github.com/18F/C2 into freeform_cart_v4

Conflicts:
	app/assets/javascripts/overlay/overlay.js
	app/assets/stylesheets/overlay.scss
	app/views/overlay/index.html.erb