Can not start the middleman server when i use the latest version of Compass (0.12.2.rc.1)

When i use the latest version of Compass (0.12.2.rc.1), i can not start the middleman server.

```ruby
gem 'middleman', '3.0.0.rc.1'
gem 'compass', '0.12.2.rc.1'
```

I got the error:

```
$ middleman server
Sass is in the process of being separated from Haml,
and will no longer be bundled at all in Haml 3.2.0.
Please install the 'sass' gem if you want to use Sass.

== The Middleman is loading
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-more-3.0.0.rc.1/lib/middleman-more/core_extensions/compass.rb:31:in `block (2 levels) in registered': undefined local variable or method `fonts_dir' for #<Middleman::Application::MiddlemanApplication1:0x007fd5cc115dd8> (NameError)
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/compass-0.12.2.rc.1/lib/compass/configuration/helpers.rb:9:in `configuration'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-more-3.0.0.rc.1/lib/middleman-more/core_extensions/compass.rb:24:in `block in registered'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/vendor/hooks-0.2.0/lib/hooks.rb:53:in `instance_exec'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/vendor/hooks-0.2.0/lib/hooks.rb:53:in `block in run_hook_for'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/vendor/hooks-0.2.0/lib/hooks.rb:49:in `each'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/vendor/hooks-0.2.0/lib/hooks.rb:49:in `run_hook_for'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/vendor/hooks-0.2.0/lib/hooks.rb:107:in `run_hook'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/core_extensions/extensions.rb:151:in `initialize'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/core_extensions/data.rb:35:in `initialize'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/application.rb:175:in `initialize'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/core_extensions/request.rb:57:in `new'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/core_extensions/request.rb:57:in `inst'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/preview_server.rb:16:in `start'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/cli/server.rb:54:in `server'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/task.rb:22:in `run'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/invocation.rb:118:in `invoke_task'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor.rb:263:in `dispatch'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/base.rb:389:in `start'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/lib/middleman-core/cli.rb:64:in `method_missing'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/task.rb:22:in `run'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/task.rb:108:in `run'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/invocation.rb:118:in `invoke_task'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor.rb:263:in `dispatch'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/thor-0.14.6/lib/thor/base.rb:389:in `start'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/bin/middleman:57:in `block in <top (required)>'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/bin/middleman:56:in `chdir'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/middleman-core-3.0.0.rc.1/bin/middleman:56:in `<top (required)>'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/bin/middleman:19:in `load'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/bin/middleman:19:in `<main>'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `eval'
	from /usr/local/rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `<main>'
```