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

src/WebRequestJsObject.cpp

Index: src/WebRequestJsObject.cpp
===================================================================
--- a/src/WebRequestJsObject.cpp
+++ b/src/WebRequestJsObject.cpp
@@ -13,18 +13,20 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <map>
 #include <AdblockPlus/JsValue.h>
 #include <AdblockPlus/WebRequest.h>
+
+#include "JsContext.h"
+#include "Thread.h"
 #include "WebRequestJsObject.h"
-#include "Thread.h"
 
 namespace
 {
   class WebRequestThread : public AdblockPlus::Thread
   {
   public:
     WebRequestThread(AdblockPlus::JsEnginePtr jsEngine, AdblockPlus::JsValueList& arguments)
         : jsEngine(jsEngine), url(arguments[0]->AsString())
@@ -52,17 +54,17 @@ namespace
       if (!callback->IsFunction())
         throw std::runtime_error("Third argument to GET must be a function");
     }
 
     void Run()
     {
       AdblockPlus::ServerResponse result = jsEngine->GetWebRequest()->GET(url, headers);
 
-      AdblockPlus::JsEngine::Context context(jsEngine);
+      AdblockPlus::JsContext context(jsEngine);
 
       AdblockPlus::JsValuePtr resultObject = jsEngine->NewObject();
       resultObject->SetProperty("status", result.status);
       resultObject->SetProperty("responseStatus", result.responseStatus);
       resultObject->SetProperty("responseText", result.responseText);
 
       AdblockPlus::JsValuePtr headersObject = jsEngine->NewObject();
       for (AdblockPlus::HeaderList::iterator it = result.responseHeaders.begin();