Make the project_path variable setable as an --app-dir option on CLI.

lib/compass/exec/project_options_parser.rb

@@ -20,6 +20,10 @@ def set_project_options(opts)
  self.options[:project_type] = project_type.to_sym
  end
 
+ opts.on('--app-dir PATH', 'The base directory for your application.') do |project_path|
+ self.options[:project_path] = project_path
+ end
+
  opts.on('--sass-dir SRC_DIR', "The source directory where you keep your sass stylesheets.") do |sass_dir|
  set_dir_or_path(:sass, sass_dir)
  end
@@ -35,7 +39,7 @@ def set_project_options(opts)
  opts.on('--javascripts-dir JS_DIR', "The directory where you keep your javascripts.") do |javascripts_dir|
  set_dir_or_path(:javascripts, javascripts_dir)
  end
- 
+
  opts.on('--fonts-dir FONTS_DIR', "The directory where you keep your fonts.") do |fonts_dir|
  set_dir_or_path(:fonts, fonts_dir)
  end