Change #to_model -> #wrapped_object

This is a breaking change, but ActiveModel already uses
to_model in a certain way.

CHANGELOG.txt

@@ -6,6 +6,8 @@
 
 * Dropped support for Rubies < 1.9.3
 
+* #to_model has been renamed to #wrapped_object
+
 == 0.12.1
 
 * Added Changelog

lib/draper/base.rb

@@ -191,7 +191,7 @@ module Draper
     # Fetch the original wrapped model.
     #
     # @return [Object] original_model
-    def to_model
+    def wrapped_object
       @model
     end
 

spec/draper/base_spec.rb

@@ -182,10 +182,9 @@ describe Draper::Base do
     end
   end
 
-  context(".model / .to_model") do
+  context(".wrapped_object") do
     it "should return the wrapped object" do
-      subject.to_model.should == source
-      subject.model.should == source
+      subject.wrapped_object.should == source
     end
   end