* update unit teting aspnet web api and some images
* update image to display unit test's Text Explorer specific to VS2017
* update mocking EF md and its images
* Change the version of Moq used to the version that is compatible with VS 2015 and VS 2017
* update further to notify Moq version
* Update link of code sample to point to newer sample that uses VS 2017
* update wording based on PR feedback