Use a LowercaseHash when :headers_hash is passed to a response.

lib/typhoeus/response.rb

@@ -18,7 +18,7 @@ def initialize(params = {})
       @request               = params[:request]
       @effective_url         = params[:effective_url]
       @mock                  = params[:mock] || false  # default
-      @headers_hash          = params[:headers_hash]
+      @headers_hash          = LowercaseHash.new(params[:headers_hash]) if params[:headers_hash]
     end
 
     # Returns true if this is a mock response.

spec/typhoeus/response_spec.rb

@@ -7,6 +7,11 @@
       response.headers_hash.should == {}
     end
 
+    it "allows header access using a different casing of the header key" do
+      response = Typhoeus::Response.new(:headers_hash => { 'content-type' => 'text/html' } )
+      response.headers_hash['Content-Type'].should == 'text/html'
+    end
+
     it "should store response_code" do
       Typhoeus::Response.new(:code => 200).code.should == 200
     end