Implemented update checking functionality

libadblockplus.gyp

Index: libadblockplus.gyp
===================================================================
--- a/libadblockplus.gyp
+++ b/libadblockplus.gyp
@@ -89,16 +89,17 @@
       'action_name': 'convert_js',
       'variables': {
         'library_files': [
           'lib/info.js',
           'lib/io.js',
           'lib/prefs.js',
           'lib/utils.js',
           'lib/elemHideHitRegistration.js',
+          'lib/updater.js',
           'adblockplus/lib/filterNotifier.js',
           'lib/init.js',
           'adblockplus/lib/filterClasses.js',
           'adblockplus/lib/subscriptionClasses.js',
           'adblockplus/lib/filterStorage.js',
           'adblockplus/lib/elemHide.js',
           'adblockplus/lib/matcher.js',
           'adblockplus/lib/filterListener.js',
@@ -147,16 +148,17 @@
       'test/DefaultFileSystem.cpp',
       'test/FileSystemJsObject.cpp',
       'test/FilterEngine.cpp',
       'test/GlobalJsObject.cpp',
       'test/JsEngine.cpp',
       'test/JsValue.cpp',
       'test/Prefs.cpp',
       'test/Thread.cpp',
+      'test/UpdateCheck.cpp',
       'test/WebRequest.cpp'
     ],
     'msvs_settings': {
       'VCLinkerTool': {
         'SubSystem': '1',   # Console
         'EntryPointSymbol': 'mainCRTStartup',
       },
     },