switch vcr web backend to fakeweb, add vcr support for nico seiga tests

test/unit/sources/nico_seiga_test.rb

@@ -7,8 +7,10 @@ module Sources
     context "The source site for nico seiga" do
       setup do
         # Sources::Strategies::NicoSeiga.new("http://lohas.nicoseiga.jp/priv/2853566?e=1361296671&h=794b3686b02edfd64c22ed2f99a4c55650371854")
-        @site = Sources::Site.new("http://seiga.nicovideo.jp/seiga/im1464351?track=ranking")
-        @site.get
+
+        VCR.use_cassette("source-nico-seiga-unit-test", :record => :new_episodes) do
+          @site = Sources::Site.new("http://seiga.nicovideo.jp/seiga/im1464351?track=ranking")
+        end
       end
 
       should "get the profile" do