Merge pull request #64 from pengwynn/master

Allow haml to be called from pages
Hide draft pages in production (closes #61).
Don't include drafts in feeds or lists.
Use the new Page#hidden method to raise 404.
Page.find_by_path returns nil if page in draft.
Upgrade Sinatra to 1.2.6.
Show usage on invalid options to nesta command.
Render Sass stylesheet in the gem (closes #66).
Renamed FixtureHelper to TempFileHelper.
Include ConfigSpecHelper in all specs.
Load plugins from gems.

The Nesta::Plugins module was renamed to Nesta::Plugin so that plugins
defined within that namespace will have a name that makes sense (such as
Nesta::Plugin::Stuff).
Create new plugins with plugin:create command.
Raise RuntimeError if generated folders exist.
Bumped version to 0.9.10.
Load Nesta::Plugin on require.
Plugins actually require 0.9.11.
Fixed files created by plugin:create.
Make metadata lookup case insensitive.
Changed default Markdown processor to redcarpet.

Tilt can render all sorts of templates, including Markdown and Textile.
When there are several Markdown processors available, Tilt will use the
first one it finds. You can also ask it to use a specific processor, so
each site can now use its Markdown processor of choice.

See #65.
Updated CHANGES.