Fix dependencies that break with ruby 1.9.3

Ruby 1.9.3 requires a recent version of RSpec 2, and simplecov
supercedes rcov on ruby 1.9+.

Gemfile.lock

@@ -1,40 +1,42 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    columnize (0.3.2)
-    diff-lcs (1.1.2)
+    diff-lcs (1.1.3)
     git (1.2.5)
-    jeweler (1.6.2)
+    jeweler (1.8.3)
       bundler (~> 1.0)
       git (>= 1.2.5)
       rake
-    linecache (0.43)
-    rake (0.9.2)
-    rcov (0.9.9)
-    rspec (2.1.0)
-      rspec-core (~> 2.1.0)
-      rspec-expectations (~> 2.1.0)
-      rspec-mocks (~> 2.1.0)
-    rspec-core (2.1.0)
-    rspec-expectations (2.1.0)
-      diff-lcs (~> 1.1.2)
-    rspec-mocks (2.1.0)
-    ruby-debug (0.10.4)
-      columnize (>= 0.1)
-      ruby-debug-base (~> 0.10.4.0)
-    ruby-debug-base (0.10.4)
-      linecache (>= 0.3)
+      rdoc
+    json (1.7.3)
+    multi_json (1.3.6)
+    rake (0.8.7)
+    rcov (1.0.0)
+    rdoc (3.12)
+      json (~> 1.4)
+    rspec (2.10.0)
+      rspec-core (~> 2.10.0)
+      rspec-expectations (~> 2.10.0)
+      rspec-mocks (~> 2.10.0)
+    rspec-core (2.10.1)
+    rspec-expectations (2.10.0)
+      diff-lcs (~> 1.1.3)
+    rspec-mocks (2.10.1)
+    simplecov (0.6.4)
+      multi_json (~> 1.0)
+      simplecov-html (~> 0.5.3)
+    simplecov-html (0.5.3)
     test-construct (1.2.0)
-    thor (0.14.6)
+    thor (0.15.2)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   jeweler (>= 1.6.2)
-  rake
+  rake (~> 0.8.7)
   rcov
-  rspec (~> 2.1.0)
-  ruby-debug
+  rspec (~> 2.10)
+  simplecov
   test-construct
   thor (>= 0.14.0)