limeSNA ported to ADALM-PLUTO

This is a Scalar Network Analyzer program initialy written for the LimeSDR mini by github user nepeee (https://github.com/nepeee/limeSNA).
I replaced the SoapySDR layer by pow tool, and added Pluto TXgain and RXgain controls to the webpage.
Sweep time is not optimal and can be improved : approx. 1 hop/s

Youtube : https://www.youtube.com/watch?v=yh-9a1fkgFA

Dependencies

pow tool : you will need to compile pow tool.
build pow tool :
```
gcc -std=gnu99 -g -o pow pow.c -liio -lm -Wall -Wextra
```
Test :
```
./pow -l 430600000 -g 40 -f 3   
```
result : 430600000 2.49 95.75
units : freq (Hz), signal (dB) computed by pow, RSSI (dB) returned by pluto through IIO
numpy (pip)
flask (pip)
flask_socketio (pip)
webbrowser (pip)
gevent (pip)
gevent-websocket (pip)
libiio

Quick setup :

cd ~  
git clone https://github.com/LamaBleu/limeSNA  
cd limeSNA  
git checkout plutosdr  
gcc -std=gnu99 -g -o pow pow.c -liio -lm -Wall -Wextra

How to use:

Install all the dependencies and run the code from a terminal with the following command:

python sna.py

After the radio is ready to use, the program starts a new web browser with the UI ( http://127.0.0.1:55555 ). Press the run button to start the frequeny sweep.
For relative("calibrated") measurements wait a full sweep and then press the "Set relative" button.