Update Jekyll up to v2.5.3.

Gemfile

@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'jekyll', '~> 2.4.0'
+gem 'jekyll', '~> 2.5'
 gem 'therubyracer'
 gem 'i18n'
 gem 'jekyll-press'

Gemfile.lock

@@ -2,15 +2,13 @@ GEM
   remote: https://rubygems.org/
   specs:
     blankslate (2.1.2.4)
-    celluloid (0.16.0)
+    classifier-reborn (2.0.3)
-      timers (~> 4.0.0)
-    classifier-reborn (2.0.1)
       fast-stemmer (~> 1.0)
     coderay (1.1.0)
-    coffee-script (2.3.0)
+    coffee-script (2.4.1)
       coffee-script-source
       execjs
-    coffee-script-source (1.8.0)
+    coffee-script-source (1.9.1.1)
     colorator (0.1)
     css_press (0.3.2)
       csspool-st (= 3.1.2)
@@ -19,30 +17,32 @@ GEM
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
-    eventmachine (1.0.3)
+    eventmachine (1.0.8)
-    execjs (2.2.1)
+    execjs (2.6.0)
     fast-stemmer (1.0.2)
-    ffi (1.9.3)
+    ffi (1.9.10)
     formatador (0.2.5)
-    guard (2.6.1)
+    guard (2.13.0)
       formatador (>= 0.2.4)
-      listen (~> 2.7)
+      listen (>= 2.7, <= 4.0)
       lumberjack (~> 1.0)
+      nenv (~> 0.1)
+      notiffany (~> 0.0)
       pry (>= 0.9.12)
+      shellany (~> 0.0)
       thor (>= 0.18.1)
-    guard-livereload (2.3.0)
+    guard-livereload (2.4.0)
       em-websocket (~> 0.5)
-      guard (~> 2.0)
+      guard (~> 2.8)
       multi_json (~> 1.8)
-    hitimes (1.2.2)
     html_press (0.8.2)
       htmlentities
       multi_css (>= 0.1.0)
       multi_js (>= 0.1.0)
-    htmlentities (4.3.2)
+    htmlentities (4.3.4)
     http_parser.rb (0.6.0)
-    i18n (0.6.11)
+    i18n (0.7.0)
-    jekyll (2.4.0)
+    jekyll (2.5.3)
       classifier-reborn (~> 2.0)
       colorator (~> 0.1)
       jekyll-coffeescript (~> 1.0)
@@ -59,63 +59,65 @@ GEM
       toml (~> 0.1.0)
     jekyll-coffeescript (1.0.1)
       coffee-script (~> 2.2)
-    jekyll-gist (1.1.0)
+    jekyll-gist (1.3.4)
-    jekyll-paginate (1.0.0)
+    jekyll-paginate (1.1.0)
     jekyll-press (0.2.1)
       html_press (>= 0.8.2)
       jekyll
       multi_css (>= 0.1.0)
       multi_js (>= 0.1.0)
-    jekyll-sass-converter (1.2.1)
+    jekyll-sass-converter (1.3.0)
       sass (~> 3.2)
-    jekyll-watch (1.1.1)
+    jekyll-watch (1.3.0)
-      listen (~> 2.7)
+      listen (~> 3.0)
-    json (1.8.1)
+    json (1.8.3)
-    kramdown (1.4.1)
+    kramdown (1.9.0)
-    libv8 (3.16.14.7)
+    libv8 (3.16.14.11)
-    liquid (2.6.1)
+    liquid (2.6.3)
-    listen (2.7.9)
+    listen (3.0.3)
-      celluloid (>= 0.15.2)
       rb-fsevent (>= 0.9.3)
       rb-inotify (>= 0.9)
     lumberjack (1.0.9)
-    mercenary (0.3.4)
+    mercenary (0.3.5)
     method_source (0.8.2)
     multi_css (0.1.0)
       css_press
     multi_js (0.1.0)
       uglifier (~> 2)
-    multi_json (1.10.1)
+    multi_json (1.11.2)
+    nenv (0.2.0)
+    notiffany (0.0.8)
+      nenv (~> 0.1)
+      shellany (~> 0.0)
     parslet (1.5.0)
       blankslate (~> 2.0)
-    posix-spawn (0.3.9)
+    posix-spawn (0.3.11)
-    pry (0.10.1)
+    pry (0.10.2)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
       slop (~> 3.4)
-    pygments.rb (0.6.0)
+    pygments.rb (0.6.3)
       posix-spawn (~> 0.3.6)
-      yajl-ruby (~> 1.1.0)
+      yajl-ruby (~> 1.2.0)
-    rb-fsevent (0.9.4)
+    rb-fsevent (0.9.6)
     rb-inotify (0.9.5)
       ffi (>= 0.5.0)
-    redcarpet (3.1.2)
+    redcarpet (3.3.3)
-    ref (1.0.5)
+    ref (2.0.0)
-    safe_yaml (1.0.3)
+    safe_yaml (1.0.4)
-    sass (3.4.4)
+    sass (3.4.18)
+    shellany (0.0.1)
     slop (3.6.0)
-    therubyracer (0.12.1)
+    therubyracer (0.12.2)
       libv8 (~> 3.16.14.0)
       ref
     thor (0.19.1)
-    timers (4.0.1)
+    toml (0.1.2)
-      hitimes
-    toml (0.1.1)
       parslet (~> 1.5.0)
-    uglifier (2.5.3)
+    uglifier (2.7.2)
       execjs (>= 0.3.0)
       json (>= 1.8.0)
-    yajl-ruby (1.1.0)
+    yajl-ruby (1.2.1)
 
 PLATFORMS
   ruby
@@ -123,6 +125,6 @@ PLATFORMS
 DEPENDENCIES
   guard-livereload
   i18n
-  jekyll (~> 2.4.0)
+  jekyll (~> 2.5)
   jekyll-press
   therubyracer