Implement decode on PositionWithoutTimestampWithMessaging

[CBielstein]

Description

The last of the remaining scenarios in the PositionInfo code is decoding PacketType.PositionWithoutTimestampWithMessaging. This PR resolves that issue.

Along with #109, this should allow APRS# to encode and decode any complete weather reports and position packets.

This was a pretty straightforward change as most of the code was already implemented. I added some encode and decode tests (encode of this already worked, only decode needed fixing, but more tests are always good!).

All that was left was to merge the "without timestamp" cases of position decode and set messaging support based on the packet type. This pattern follows the decode of the "with timestamp" types just below in the same file.

This will resolve #92.

Changes

• Added both encode and decode test cases for PacketType.PositionWithoutTimestampWithMessaging
• Slight refactor on PositionInfo.cs to support decode of PacketType.PositionWithoutTimestampWithMessaging
• Removed TODO comment for this issue from the code

Validation

• Build and tests passing
• Decode works from APRS-IS on the console app. See screenshot below.

[CBielstein]

so does it mean we need to have a better approach of handling the timeouts or is there a general practice around setting that time?

@eddywine It's starting to look like that. I suspect the error is in how I'm computing timeout in the test code since the actual decode is only taking milliseconds... if it keeps causing an issue and needing to be bumped up, we'll have to address it more directly, I suppose.