A multi-platform tool to save Touchstone files from the NanoVNA.
Sweep frequency spans in segments to gain more than 101 data points,
and display and analyze the resulting data.

Current features:
* Reading data from a NanoVNA
* Splitting a frequency range into multiple segments to increase resolution
(tried up to >10k points)
* Zoom into frequency displays to examine details
* Averaging data for better results particularly at higher frequencies
* Displaying data on multiple chart types, such as Smith, LogMag, Phase and
VSWR-charts, for both S11 and S21
* Displaying markers, and the impedance, VSWR, Q, equivalent
capacitance/inductance etc. at these locations
* Displaying customizable frequency bands as reference, for example amateur
radio bands
* Exporting and importing 1-port and 2-port Touchstone files
TDR function (measurement of cable length)
* Display of both an active and a reference trace
* Live updates of data from the NanoVNA, including for multi-segment sweeps
* In-application calibration, including compensation for non-ideal
calibration standards
* Customizable display options, including "dark mode"
* Exporting images of plotted values