WebCL Conformance test suite update for review.

    Fixes the below issues ::
    [Khronos #16] Security : Add test cases to check for memory initialization.
    Add test cases for rowPitch values with createImage()
    Create a commandQueue only if device supports the property.
    Fix enqueue{Read, Write} Image for 'hostRowPitchInvalid' in bindingTesting
    Add a test case for webclplatform::getdevices() without parameters.

    HomePage : Correction in obtaining DEFAULT device.
    HomePage : Display test case number only if its available

    Refractor enqueueCopy* API test cases.
    Add functionality tests for WebCLContext :: createCommandQueue
    Add functionality tests for createSampler API
    Add functionality tests for enqueue{Read, Write} Buffer API
    Add functionality tests for enqueue {Read/ Write} image API.

    createCommandQueue.html uses DEVICE_TYPE_ALL for creating context
    Refractor HTMLCanvasElement API's.
    Refractor all enqueue*Rect test cases.

    Add testcases for createContext in extension: KHR_gl_sharing.
    Add testcases for createFromGLRenderbuffer API in extension: KHR_gl_sharing.
    Add testcases for createFromGLTexture API in extension: KHR_gl_sharing.
    Add testcases for createFromGLBuffer API in extension: KHR_gl_sharing.

    Contributors :
    SRI-B : Shilpa Shri, Sharath Kamath.
    SRA : Antonio, Steven and Igor.