VOR localizer feature
The VOR demodulator released previously has been split in a new VOR demodulator that takes care of demodulating a single VOR and a VOR localizer feature to position the receiving station on a map using the decoded radial directions from several VOR demodulators. The positioning works like the original VOR demodulator positioning.
The VOR localizer can service more VORs than the individual VOR demodulators available by controlling these demodulators in a round robin fashion. It can also use several receivers to cover different frequency ranges in the 10 MHz wide band dedicated to VORs (108 - 118 MHz).
The original VOR demodulator is implemented with sub channels that carry out the demodulation of individual VORs but as they all run on the same thread the entanglement of their FIFOs can be an issue with packet drops depending on your system and its current load. This limitation is lifted with the single channel VOR and VOR localizer combination.
This implements issue #729