SDK v5.5

* commit 'efd1feed77a9b1193fa1e5b0c682c27e0cc97d17': (54 commits)
  Updated Facebook Native Adapter
  Updated version
  Merge pull request #377 in MOBILE-SDK/app_mobile-sdk-ios from ObjectiveC_Optional_Convention to develop
  Merge pull request #397 in MOBILE-SDK/app_mobile-sdk-ios from MS-3902_Deprecated_API_Removal to develop
  Native Only Unit test
  Fixed Buidling of UnitTestApp
  Mediation Adaptor Updated
  Merge pull request #385 in MOBILE-SDK/app_mobile-sdk-ios from MS-3778_Video_AspectRatio to develop
  code review feedback
  update version
  code review
  remove sample apps
  fix comments
  tmp check in
  use category instead of subclassing
  move variables to inside .m
  review comments
  tmp checking two files for development
  fix review comments
  modify Facebook adapter code
  ...

.gitignore

@@ -1,9 +1,10 @@
 ####
 # Binary build product files
-
+*.framework
 **/out
 **/Products
-
+**/out_device
+**/out_simulator
 ########################################################################################
 # macOS.gitignore
 # https://github.com/github/gitignore/blob/master/Global/macOS.gitignore
@@ -131,4 +132,7 @@ fastlane/test_output
 # After new code Injection tools there's a generated folder /iOSInjectionProject
 # https://github.com/johnno1962/injectionforxcode
 
-iOSInjectionProject/
+iOSInjectionProject/
+
+xcshareddata
+Pods