Make Rspec 3 compliant

Change explicit use of `example` variable to using the block value that
is passed in to examples and before/after hooks.

lib/capybara/rspec.rb

@@ -15,10 +15,10 @@ RSpec.configure do |config|
       Capybara.use_default_driver
     end
   end
-  config.before do
+  config.before do |example|
     if self.class.include?(Capybara::DSL)
-      Capybara.current_driver = Capybara.javascript_driver if example.metadata[:js]
-      Capybara.current_driver = example.metadata[:driver] if example.metadata[:driver]
+      Capybara.current_driver = Capybara.javascript_driver if ex.metadata[:js]
+      ampleCapybara.current_driver = ex.metadata[:driver] if ex.metadata[:driver]
     end
   end
 end

spec/rspec/features_spec.rb

@@ -15,7 +15,7 @@ feature "Capybara's feature DSL" do
     page.should have_content('Hello world!')
   end
 
-  scenario "preserves description" do
+  scenario "preserves description" do |example|
     example.metadata[:full_description].should == "Capybara's feature DSL preserves description"
   end
 
@@ -41,11 +41,11 @@ feature "Capybara's feature DSL" do
       page.should have_content 'Hello world!'
     end
 
-    scenario 'are marked in the metadata as capybara_feature' do
+    scenario 'are marked in the metadata as capybara_feature' do |example|
       example.metadata[:capybara_feature].should be_true
     end
 
-    scenario 'have a type of :feature' do
+    scenario 'have a type of :feature' do |example|
       example.metadata[:type].should eq :feature
     end
   end