Remove to_binary, closes #243 and #340

After investigating this thoroughly, I have come
to the conclusion that the need for to_binary
came from a bug in rack, which has subsequently
been fixed. If warnings show up after this change
they should disappear with the release of rack 1.3

lib/capybara/rack_test/browser.rb

@@ -43,7 +43,7 @@ class Capybara::RackTest::Browser
     end
 
     reset_cache!
-    send(method, to_binary(path), to_binary( attributes ), env)
+    send(method, path, attributes, env)
     follow_redirects!
   end
 
@@ -85,20 +85,6 @@ protected
     Rack::MockSession.new(app, current_host)
   end
 
-  def to_binary(object)
-    return object unless Kernel.const_defined?(:Encoding)
-
-    if object.respond_to?(:force_encoding)
-      object.dup.force_encoding(Encoding::ASCII_8BIT)
-    elsif object.respond_to?(:each_pair) #Hash
-      {}.tap { |x| object.each_pair {|k,v| x[to_binary(k)] = to_binary(v) } }
-    elsif object.respond_to?(:each) #Array
-      object.map{|x| to_binary(x)}
-    else
-      object
-    end
-  end
-
   def request_path
     last_request.path
   rescue Rack::Test::Error

spec/driver/rack_test_driver_spec.rb

@@ -25,29 +25,6 @@ describe Capybara::RackTest::Driver do
     end.should raise_error(ArgumentError)
   end
 
-  if '1.9'.respond_to?(:encode)
-    describe "with non-binary parameters" do
-
-      it "should convert attribute values to binary" do
-        output = capture(:stderr) {
-          @driver.visit('/mypage', :param => 'µ')
-        }.should_not =~ %r{warning: regexp match /.../n against to UTF-8 string}
-      end
-
-      it "should convert attribute with Array to binary" do
-        output = capture(:stderr) {
-          @driver.visit('/mypage', :param => ['µ'])
-        }.should_not =~ %r{warning: regexp match /.../n against to UTF-8 string}
-      end
-
-      it "should convert path to binary" do
-        output = capture(:stderr) {
-          @driver.visit('/mypage'.encode('utf-8'))
-        }.should_not =~ %r{warning: regexp match /.../n against to UTF-8 string}
-      end
-    end
-  end
-
   it_should_behave_like "driver"
   it_should_behave_like "driver with header support"
   it_should_behave_like "driver with status code support"