Add Viterbi decoder

[BatchDrake]

Add a GUI to configure a Viterbi decoder. Some insights by EA4GPZ:

• Most people use CCSDS polynomials
• These polynomials can be applied in different order, and one of them may be inverted. See http://destevez.net/2017/01/coding-for-hit-satellites-and-other-ccsds-satellites/
• Bits must be grouped appropriately to fit the beginning of each codeword. If the size of the codeword is n, there will be n possible groupings. This means that the Trellis tree must be traversed n times in parallel with increasing symbol offsets.

Summary: 95% of the time we will have CCSDS polynomials with rate = 1/2 and k = 7. This default configuration must appear somewhere in the GUI (like a preset)