Updated the dependencies.

This was specifically for the rest-client dependency for coveralls, as there was
a security risk in the prior version.

Note that the security issue does not impact RubyTree in any way.

Gemfile.lock

@@ -8,32 +8,32 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    coveralls (0.7.9)
+    coveralls (0.7.11)
       multi_json (~> 1.10)
-      rest-client (~> 1.7)
+      rest-client (>= 1.6.8, < 2)
       simplecov (~> 0.9.1)
       term-ansicolor (~> 1.3)
       thor (~> 0.19.1)
     docile (1.1.5)
     json (1.8.2)
     mime-types (2.4.3)
     multi_json (1.10.1)
-    netrc (0.10.2)
+    netrc (0.10.3)
     power_assert (0.2.2)
     rake (10.4.2)
     rdoc (4.2.0)
       json (~> 1.4)
-    rest-client (1.7.2)
+    rest-client (1.7.3)
       mime-types (>= 1.16, < 3.0)
       netrc (~> 0.7)
     rtags (0.97)
     rtagstask (0.0.4)
       rtags (> 0.0.0)
-    simplecov (0.9.1)
+    simplecov (0.9.2)
       docile (~> 1.1.0)
       multi_json (~> 1.0)
-      simplecov-html (~> 0.8.0)
-    simplecov-html (0.8.0)
+      simplecov-html (~> 0.9.0)
+    simplecov-html (0.9.0)
     structured_warnings (0.2.0)
     term-ansicolor (1.3.0)
       tins (~> 1.0)