Added rx modes, adjusted some interface and rx parameters

[AB9IL]

These changes improved my experience listening to AM broadcasts, aero and maritime utilities, and CW stations.

• added servers to kiwi.list
• included synchronous AM modes SAM, SAL, and SAU
• font color for main rx indications
• AGC settings for CW
• Audio buffer and chunk settings adjusted for smoother streaming. Using 2 chunks made a significant difference.
• deleted some areas of trailing whitespace

Everything works nicely on my Ubuntu respins, with current pygame and sounddevice modules.

** This is a resubmission, as I made more code changes after the earlier pull request.