UpdateManager configuration

- Implemented UpdateManagerConfiguration class to store the
configuration data specific to UpdateManager
- This class can be serialized and de-serialized into/from xml file.
- UpdateManager initializes the configuration from
UpdateManagerConfig.xml file if present in Dynamo installation,
otherwise by default it will point to production servers for
UpdateFileLocations and Signature file location.
- In Debug build it creates UpdateManagerConfig.xml file if not present
and saves the default configuration data. The same file can be used to
redirect the update location to the dev S3-bucket from a release build.
Addressing review comments
Adding testcase for UpdateManagerConfiguration
Merge pull request #2663 from Conceptual-Design/UpdateManager

UpdateManager configuration
Refactoring code and tests

1. Address naming conventions and removing redundant args
2. Added PreviewChangeSetTests file where all preview tests should go in
3. Refactor common code to TestFrameWork
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into VMGraphTools