Use yajl since it is already a dependency

Both JSON and Yajl were listed as dependencies. Pygments.rb already requires yajl, so let's just use that instead of using both.

Rakefile

@@ -1,7 +1,7 @@
-require 'json'
 require 'rake/clean'
 require 'rake/testtask'
 require 'yaml'
+require 'yajl'
 
 task :default => :test
 
@@ -19,15 +19,13 @@ end
 
 task :samples do
   require 'linguist/samples'
-  require 'yajl'
-  data = Linguist::Samples.data
-  json = Yajl::Encoder.encode(data, :pretty => true)
-  File.open('lib/linguist/samples.json', 'w') { |io| io.write json }
+  json = Yajl.dump(Linguist::Samples.data, :pretty => true)
+  File.write 'lib/linguist/samples.json', json
 end
 
 task :build_gem => :samples do
   languages = YAML.load_file("lib/linguist/languages.yml")
-  File.write("lib/linguist/languages.json", JSON.dump(languages))
+  File.write("lib/linguist/languages.json", Yajl.dump(languages))
   `gem build github-linguist.gemspec`
   File.delete("lib/linguist/languages.json")
 end
@@ -71,11 +69,11 @@ namespace :benchmark do
     reference_file = ENV["REFERENCE"]
     candidate_file = ENV["CANDIDATE"]
 
-    reference = JSON.parse(File.read(reference_file))
+    reference = Yajl.load(File.read(reference_file))
     reference_counts = Hash.new(0)
     reference.each { |filename, language| reference_counts[language] += 1 }
 
-    candidate = JSON.parse(File.read(candidate_file))
+    candidate = Yajl.load(File.read(candidate_file))
     candidate_counts = Hash.new(0)
     candidate.each { |filename, language| candidate_counts[language] += 1 }
 
@@ -125,14 +123,12 @@ namespace :classifier do
 
   def each_public_gist
     require 'open-uri'
-    require 'json'
-
     url = "https://api.github.com/gists/public"
 
     loop do
       resp = open(url)
       url = resp.meta['link'][/<([^>]+)>; rel="next"/, 1]
-      gists = JSON.parse(resp.read)
+      gists = Yajl.load(resp.read)
 
       for gist in gists
         for filename, attrs in gist['files']