Improve Channelised Data Quality (lofar_cli_stokes.c)

[David-McKenna]

Increases channelised data quality through the user of overlapping data in FFT windows, using smaller FFT windows for increased performance, and adding a baseline support for pulsar coherent dedispersion

TODO:

• Non-even channelisation factor support
  • Will probably achieve this by removing access to packetsPerIteration, and controlling it based on the requested input
• General code cleanup/documentation (cleanup done, documentation needed)
• Move debug information to the verbose flag
• Fix the no-metadata segfault when it attempts to calculate associated frequencies (how did this get past the tests?)
• Correlated voltages output mode for faster generation than DADA/digifil glue
• [~] Account for partial reads in the end block (accounted for by just exiting. Not great, but it'll work.)
  • Get all useful data in the last block, up to the last full FFT operation. This will require adjusting the input parameters for overlapAndPad, for both "intended" and "real input" dimensions. Maybe split it into a new func call?
• Add metadata overrides for nbit, processing mode to silence warnings