refactored code to resolve some non critical issues
Added new unit tests and improved file validations
Entirely refactored VirustotalPublicV2ImplTest and its dependancies to be more unit test friendly
updated unit tests
Refactored the code to be more testable and updated tests accordingly
(1) mocked HTTPRequest and updated test testScanWithInvalidApiKey
(2) modified testScanFile to use mocks