Update to RSpec 3.4

RSpec 3 was [released](rspec/rspec@2d9f9e8) June 1, 2014 and 3.4.0 was [released](rspec/rspec@7f0ec7a) 9 days ago. The whole test suite seems to run without modification. This is in the spirit of trying to keep gems up to date so there isn't a lot of work to do later on.

Gemfile.lock

@@ -14,14 +14,19 @@ GEM
     i18n (0.7.0)
     json (1.8.3)
     minitest (5.8.0)
-    rspec (2.14.1)
-      rspec-core (~> 2.14.0)
-      rspec-expectations (~> 2.14.0)
-      rspec-mocks (~> 2.14.0)
-    rspec-core (2.14.8)
-    rspec-expectations (2.14.5)
-      diff-lcs (>= 1.1.3, < 2.0)
-    rspec-mocks (2.14.6)
+    rspec (3.4.0)
+      rspec-core (~> 3.4.0)
+      rspec-expectations (~> 3.4.0)
+      rspec-mocks (~> 3.4.0)
+    rspec-core (3.4.1)
+      rspec-support (~> 3.4.0)
+    rspec-expectations (3.4.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.4.0)
+    rspec-mocks (3.4.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.4.0)
+    rspec-support (3.4.1)
     thread_safe (0.3.5)
     tzinfo (1.2.2)
       thread_safe (~> 0.1)