2014-06-24 Sharath Kamath  <s.kamath@samsung.com>

        Add implementation to verify INVALID_IMAGE_SIZE in createImage

        Fixed #528

        Caching the values of DEVICE_IMAGE2D_MAX_WIDTH and
        DEVICE_IMAGE2D_MAX_HEIGHT of all the devices associated with
        the context.

        This HashMap can be used by createImage() & enqueue* API's to check validity of the
        width & height send by user. Adding supportsWidthHeight() method for the same.

        Reviewed by Antonio.

        Conformance tests:
        conformance/bindingTesting/contextAndCreate/cl_context_createImage.html
        conformance/extension/WEBCL_html_image/cl_context_createImage_with_HTMLCanvasElement.html
        conformance/extension/WEBCL_html_image/cl_context_createImage_with_HTMLImageElement.html
        conformance/extension/WEBCL_html_image/cl_context_createImage_with_imageData.html

        * Modules/webcl/WebCLContext.cpp:
        (WebCore::WebCLContext::create):
        (WebCore::WebCLContext::WebCLContext):
        (WebCore::WebCLContext::createImage2DBase):
        * Modules/webcl/WebCLContext.h: