Added QueueBase and SenderBase
Added tests for QueueBase and SenderBase
Added sync and async sender and queue
Hooked sync queue and sender into channel

Other changes
- Removed TelemetrySender class and assocaited tests
- Fixed up code and tests to work with the new queue and sender
- Everything under channel is now fully documented
Added async sender and queue tests.
Added tests for sync sender and queue
Updated comments for data contracts

Other changes
- Minor cleanup to contract tests
- Fixed child module import on Python 3.x
- Handle serialization of optional values better
Merge pull request #1 from Microsoft/feature/queue_and_sender

Feature/queue and sender