Get rid of dependencies on v8.h in public header files

libadblockplus.gyp

 {
   'conditions': [[
     # We don't want to use curl on Windows, skip the check there
     'OS=="win"',
     {
       'variables': {
         'have_curl': 0
       }
     },
     {
@@ skipping 13 matching lines @@
     ],
     'dependencies': ['third_party/v8/tools/gyp/v8.gyp:v8'],
     'sources': [
       'src/AppInfoJsObject.cpp',
       'src/ConsoleJsObject.cpp',
       'src/DefaultLogSystem.cpp',
       'src/DefaultFileSystem.cpp',
       'src/FileSystemJsObject.cpp',
       'src/FilterEngine.cpp',
       'src/GlobalJsObject.cpp',
+      'src/JsContext.cpp',
       'src/JsEngine.cpp',
+      'src/JsError.cpp',
       'src/JsValue.cpp',
       'src/Thread.cpp',
       'src/Utils.cpp',
       'src/WebRequestJsObject.cpp',
       '<(INTERMEDIATE_DIR)/adblockplus.js.cpp'
     ],
     'direct_dependent_settings': {
       'include_dirs': ['include']
     },
     'export_dependent_settings': ['third_party/v8/tools/gyp/v8.gyp:v8'],
@@ skipping 98 matching lines @@
       'test/WebRequest.cpp'
     ],
     'msvs_settings': {
       'VCLinkerTool': {
         'SubSystem': '1',   # Console
         'EntryPointSymbol': 'mainCRTStartup',
       },
     },
   }]
 }