Changed the rendering of partials for the classroom show page.

Now using render '_partial name' in the classroom controller instead of
render partial: '_partial name'.  Also removed <% yield %> in the show.html.erb file.
Slightly tweeked the html on show.html.erb to correctly use css.
Preffering css_fix layout over what was on master.

Conflicts:
	app/views/classroom/_teacher.html.erb
Merge pull request #28 from whoisglover/css_fix

Css fix