Allow Rails 3.1 to select the 'turn' gem it wants to use

Rails 3.1.x has code which checks which version of ruby is being run,
and based on the result, selects a version of turn.

For 1.9.3+, it selects "~> 0.8.3"; for everything else, it selects "0.8.2".

If we remove turn from the Appraisals, but have travis install both versions
that rails might potentially need, the in-generated-app Gemfile building should
work correctly.

.travis.yml

@@ -4,6 +4,8 @@ rvm:
   - jruby-19mode
 before_install:
   - gem update --system
+  - gem install turn --version 0.8.2
+  - gem install turn --version 0.8.3
 jdk:
   - openjdk6
 gemfile:

Appraisals

@@ -13,7 +13,6 @@ appraise "rails3.1" do
   gem "sass-rails"
   gem "coffee-rails"
   gem "uglifier"
-  gem "turn"
   gem "sqlite3", ">= 1.3.4", platforms: :mri
   gem "activerecord-jdbcsqlite3-adapter", "~> 1.2.5", platforms: :jruby
   gem "minitest-rails"

gemfiles/rails3.1.gemfile

@@ -6,7 +6,6 @@ gem "rails", "3.1.9"
 gem "sass-rails"
 gem "coffee-rails"
 gem "uglifier"
-gem "turn"
 gem "sqlite3", ">= 1.3.4", :platforms=>:mri
 gem "activerecord-jdbcsqlite3-adapter", "~> 1.2.5", :platforms=>:jruby
 gem "minitest-rails"

gemfiles/rails3.1.gemfile.lock

@@ -36,7 +36,6 @@ GEM
       activesupport (= 3.1.9)
     activesupport (3.1.9)
       multi_json (>= 1.0, < 1.3)
-    ansi (1.4.3)
     appraisal (0.5.1)
       bundler
       rake
@@ -145,8 +144,6 @@ GEM
     treetop (1.4.12)
       polyglot
       polyglot (>= 0.3.1)
-    turn (0.9.6)
-      ansi
     tzinfo (0.3.35)
     uglifier (1.3.0)
       execjs (>= 0.3.0)
@@ -171,5 +168,4 @@ DEPENDENCIES
   sass-rails
   sqlite3 (>= 1.3.4)
   therubyrhino
-  turn
   uglifier