Rewrite of noaa_apt_sink

Rewrite of the noaa_apt_sink using the line synchronisation scheme from https://github.com/LongHairedHacker/apt-decoder/. The new implementation has been designed as a drop in replacement with the same interface. The code style/formating has been matched to the other source files in this repo.

Comments here or to ar3itrary in the matrix/irc-channel.

Differences to the previous implementation:

• Uses png++ instead of plain libpng
  • Nicer interface and allowing for cleaner code
  • libpng++ should be available on any standard linux distro
  • fewer png internals exposed, less potential for mistakes
  • Higher memory consumption as the whole image is kept in RAM (approx. 4MB)
  • As png++ is only a wrapper around libpng, it consists solely of header files and does not provide its own shared object. Therefore it is only a build dependency required at compile time, not run time.
• More robust syncing code, ported from apt-decoder
  • Uses a fuzzy matching/correlation to detect sync patterns
  • Syncs on A and B patterns
  • Resyncs twice on each line, if possible
    • Considerably reduces slating (see image below)
  • Tries to fill any gaps in the image generated with data from the modules sample history
• Images are written to disk every 250 lines, to have partial images even in case of crashes