Session upgrades

This is to add API Key support to the .Net toolkit. All code changes for API Key that are not strictly for refactor are done in a single commit with comment of "Adding ability to use API Keys for authentication."

All refactor code changes are done separately for clarity in what actually changed.

Breaking Changes:
- Refactor of code base to add namespaces for organization of code.
- Change of method signature for RallyRestApi constructors to support API Key
- Moves some properties to their proper class (Ex: moved from RallyRestApi to ConnectionInfo)
- Changed casing on some methods to follow Microsoft standard for libraries.