Implemented more of the Deliverable calculations

* Added deliverable.score
* Added fixed_deliverable.score as 0
* Added deliverable.budget_ratio

  #1136

spec/models/fixed_deliverable_spec.rb

@@ -0,0 +1,8 @@
+require File.dirname(__FILE__) + '/../spec_helper'
+
+describe FixedDeliverable, '.score' do
+  it 'should always be 0' do
+    @deliverable = FixedDeliverable.new({ :subject => 'test' })
+    @deliverable.score.should eql(0)
+  end
+end