Added link for new Image Service docs for 2015
Added link for new Image Service docs for 2015

Microsoft/VSSDK-Extensibility-Samples,yannduran/VSSDK-Extensibility-Samples,Microsoft/VSSDK-Extensibility-Samples,AmadeusW/VSSDK-Extensibility-Samples,yannduran/VSSDK-Extensibility-Samples,AmadeusW/VSSDK-Extensibility-Samples