Commented Task: Add Test Cases for All the current methods that does not [1785]

Possibility to Mock<IToken> to get the results we expect instead of directly performing the queries.
Comments: Associated with changeset 33813: Version 0.9.0.0
- Completely Tested SavedSearch Controller
- Tested SearchController.SearchController
- Tested SearchController.SearchQueryExecutor
- Created a constant variable in TweetinviCore.TweetinviConstants to provide the same DefaultId value accross the library.
- Updated the classes using this default value.
- Updated Controllers result to be IEnumerable instead of List
- Classes that user have a direct access to will continue to return lists in order to ease their development.
- Updated http queries to be https queries