Finally remove deprecated interpolation syntax

The interpolation syntax "{{foo}}" has been deprecated since 0.4.0 (ruby-i18n@8894ee5) and is no being removed. Please use the (Ruby 1.9 native) interplation syntax "%{foo}" instead.

lib/i18n/backend/base.rb

@@ -10,7 +10,6 @@ module Base
 
       RESERVED_KEYS = [:scope, :default, :separator, :resolve, :object, :fallback]
       RESERVED_KEYS_PATTERN = /%\{(#{RESERVED_KEYS.join("|")})\}/
-      DEPRECATED_INTERPOLATION_SYNTAX_PATTERN = /(\\)?\{\{([^\}]+)\}\}/
 
       # Accepts a list of paths to translation files. Loads translations from
       # plain Ruby (*.rb) or YAML files (*.yml). See #load_rb and #load_yml
@@ -150,16 +149,6 @@ def pluralize(locale, entry, count)
         def interpolate(locale, string, values = {})
           return string unless string.is_a?(::String) && !values.empty?
 
-          string = string.gsub(DEPRECATED_INTERPOLATION_SYNTAX_PATTERN) do
-            escaped, key = $1, $2.to_sym
-            if escaped
-              "{{#{key}}}"
-            else
-              warn_syntax_deprecation!(locale, string)
-              "%{#{key}}"
-            end
-          end
-
           values.each do |key, value|
             value = value.call(values) if interpolate_lambda?(value, string, key)
             value = value.to_s unless value.is_a?(::String)

lib/i18n/tests/interpolation.rb

@@ -54,13 +54,6 @@ module Interpolation
         assert_equal 'Hi Yehuda!', interpolate(:interpolate, :name => 'Yehuda')
       end
 
-      test "interpolation: works with the deprecated syntax" do
-        deprecation = capture(:stderr) do
-          assert_equal 'Hi David!', interpolate(:default => 'Hi {{name}}!', :name => 'David')
-        end
-        assert_match "The {{key}} interpolation syntax in I18n messages is deprecated", deprecation
-      end
-
       test "interpolation: given the translation is in utf-8 it still works" do
         assert_equal 'Häi David!', interpolate(:default => 'Häi %{name}!', :name => 'David')
       end