new sample screenshots for CocoaPods version 1.2.0

ProjectOxfordFace.podspec

@@ -7,7 +7,7 @@ Pod::Spec.new do |s|
                    Integrate Microsoft Project Oxford Face APIs into your iOS App!
                    DESC
   s.homepage         = "https://github.com/Microsoft/Cognitive-Face-iOS"
-  s.screenshots      = "https://raw.githubusercontent.com/Microsoft/ProjectOxford-ClientSDK/master/Face/iOS/SampleScreenshots/SampleScreenshot1.png", "https://raw.githubusercontent.com/Microsoft/ProjectOxford-ClientSDK/master/Face/iOS/SampleScreenshots/SampleScreenshot2.png", "https://raw.githubusercontent.com/Microsoft/ProjectOxford-ClientSDK/master/Face/iOS/SampleScreenshots/SampleScreenshot3.png", "https://raw.githubusercontent.com/Microsoft/ProjectOxford-ClientSDK/master/Face/iOS/SampleScreenshots/SampleScreenshot4.png"
+  s.screenshots      = "https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot1.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot2.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot3.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot4.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot5.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot6.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot7.jpg","https://github.com/Microsoft/Cognitive-Face-iOS/raw/master/SampleScreenshots/SampleScreenshot8.jpg"
   s.license          = 'MIT'
   s.author           = { "Project Oxford SDK" => "oxfordGithub@microsoft.com" }
   s.source           = { :git => "https://github.com/Microsoft/Cognitive-Face-iOS.git", :branch => "master" }