B"H decode more data, etc.

- decodes a bit more information
- misc. small changes
Merge pull request #19 from hhm0/decoding

decode more squawk codes
Merge pull request #20 from hhm0/network_disabling

make network services disable-able
B"H view1090: do not block on network
Merge branch 'master' of https://www.github.com/MalcolmRobb/dump1090
Merge branch 'interactive_mode_nonblock'