Basic styles for popovers
Issue #185 - Add support for conditionally display Dashboard sections at run-time

Provide a method name or Proc object to conditionally render a section at run time
  section "Membership Summary", :if => :memberships_enabled?
  section "Membership Summary", :if => Proc.new { current_admin_user.account.memberships.any? }
ActiveAdmin::Scope.new now accepts options hash, stores :if as block, ActiveAdmin::Views::Scopes component optionally displays the scope if the block returns true.

If no :if block is provided, the scope defaults to shown.  Updated cukes to reflect & test these changes.
Split stylesheets into more different files to make them easier to work with
Restyled panel/table headers
Made some changes to how scopes are rendered, also styled em with general table tools buttons style.
Getting pagination tests to pass from the changes that were made
Various style improvements for buttons, sections and table tools.
Built basic popover component
Built action list popover on top of popover
Merge branch 'popovers' into batch-edit-ui

Conflicts:
	app/assets/stylesheets/active_admin/_base.css.scss
Action list popovers can now have IDs.  Popovers are now hidden through inline styles rather than the "hidden" class
Add braces around the first argument to redirect_to

Without this the notices become parameters on the URL
Styled disabled and selected state of table tools buttons
Prototyping checking rows interaction
Bunch of style and interaction improvements for batch actions: 
- Table rows highlight when selected
- Better selected state for batch action button
- More spacing between titlebar and page content
and more...
table_for cells now have class names based on content
More table tools JS and style tweaks
Added a glow effect to batch actions button when selected
Documented action items