Implemented update checking functionality

libadblockplus.gyp

 {
   'conditions': [[
     # We don't want to use curl on Windows and Android, skip the check there
     'OS=="win" or OS=="android"',
     {
       'variables': {
         'have_curl': 0
       }
     },
     {
@@ skipping 76 matching lines @@
     ],
     'actions': [{
       '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',
           'adblockplus/lib/synchronizer.js',
           'adblockplus/chrome/content/ui/subscriptions.xml',
@@ skipping 38 matching lines @@
       'test/AppInfoJsObject.cpp',
       'test/ConsoleJsObject.cpp',
       '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',
       },
     },
   }]
 }