Minor-update some gems: liquid, nokogiri and spring.

- liquid to 2.6.2 to remove a duplicated key warning.
- nokogiri to 1.6.6.2 to fix a problem with :nth(n) selector, etc.
- spring to 1.3.3 to fix a problem with rbenv.

Gemfile.lock

@@ -202,7 +202,7 @@ GEM
     launchy (2.4.2)
       addressable (~> 2.3)
     libv8 (3.16.14.7)
-    liquid (2.6.1)
+    liquid (2.6.2)
     listen (2.7.9)
       celluloid (>= 0.15.2)
       rb-fsevent (>= 0.9.3)
@@ -216,7 +216,7 @@ GEM
       thread_safe (~> 0.3, >= 0.3.1)
     method_source (0.8.2)
     mime-types (2.4.3)
-    mini_portile (0.6.1)
+    mini_portile (0.6.2)
     minitest (5.5.0)
     mqtt (0.3.1)
     multi_json (1.10.1)
@@ -226,7 +226,7 @@ GEM
     naught (1.0.0)
     net-ftp-list (3.2.8)
     netrc (0.10.3)
-    nokogiri (1.6.4)
+    nokogiri (1.6.6.2)
       mini_portile (~> 0.6.0)
     oauth (0.4.7)
     oauth2 (0.9.4)
@@ -363,7 +363,7 @@ GEM
     slop (3.6.0)
     spectrum-rails (1.3.4)
       railties (>= 3.1)
-    spring (1.3.2)
+    spring (1.3.3)
     spring-commands-rspec (1.0.2)
       spring (>= 0.9.1)
     sprockets (2.11.0)