Basic drawer functionality.

This is the basic interactions for the drawer.  It lives in DrawerView.
Other views that will live in the drawer need to be registered with
DrawerView.registerView and implement a drawerButton, drawerOpenEvents and
drawerCloseEvents method.

The general concept of the drawer is that it tries to stay as agnostic to
the content of the inside views as possible.  DrawerView fires
``open:drawer`` and ``close:drawer`` events when the drawer is opened or
closed.  AppView listens for these events to set a class on the main
container view which lets us use CSS for setting the width of the drawer.
Tweak drawer styling, resizing

Rotating the button text requires some hacking in Javascript.
Resize section layouts when drawer is open
Merge branch 'develop' into help_drawer
Recompile CSS

Up to cf2fb909d23d9cea44efc84b66565cd1033ff0bc
Show container help in drawer
remove 1140 grid from story builder, add 100px grid.
Integrate grid into style.css

This is done by changing grid.css to be a LESS file (really this just
involved changing the filename extension) and importing it at the top
of base.less.

The real motivation for this is to let us use the different grid classes
as mixins. This lets us use just semantic class names instead of peppering
our markup with .container_12 and .grid_6.  Furthermore it lets us have
the ease of using the grid convenince classes without having to put the
presentational class names in the Backbone view declarations.  Ultimately,
it should make the code more maintainable because all the presentational
stuff lives in the same place (the LESS stylesheets) and there should be
minimal editing of the HTML templates or Backbone views to change the
grid.

The only drawback is that using the grid classes as mixins replicates the
style definitions, which would increase the size of the final CSS.  I'm
thinking this trade-off is worth it in terms of making the styles more
maintainable.

This commit also includes giving most of the builder views a common CSS
class name of 'view-container' (which gets the .container_12 mixin in
builder.less).
Merge branch 'develop' into builder_redesign

Conflicts:
	static/js/builder/views.js
Clone commonOptions

The view constructor replaces this.options with options and extends options
with the properties of the options declared on the View.  So passing
commonOptions to subsequent view constructors gives each subsequent view
the options modified by the previous view.  Cloning the commonOptions object
before passsing it to each view constructor avoids this problem.

Closes #360.
Separate title and workflow navigation bars

Add the structure for the title and workflow navigation bars.

I still need to rework how the section nav view is rendered.  Right now it
obscures the workflow nav view.
Move next/previous workflow buttons

Move the buttons that navigate between the next and previous workflow
steps into the workflow bar
Rework display of section list

Remove show/hiding functionality
Make header have a fixed position.
s/defaults/options/

Continuation of the cleanup from 59f46a5d4e2dbaca3fa6cc2f332f26687d8df351
some work on the builder header styling.
Drawer buttons as views

This cleans up the rendering logic a lot and also makes it easier to show
the template name.
merge pull request from piton foundation and fix conflicts. update styling to account for markup changes where necessary.
Merge remote branch 'eric/builder_redesign' into builder_redesign
Rename layout.less to story_layout.less

The name was confusing as it seemed to suggest theme-wide layout when it's
actually the arrangement of assets in a story section.

Closes #361