Fix VNA reading and improve plotting

- Fix VNA readings
  -- Load VNA config (and calibration) from file.
      The *.znxml file has to be prepared in advance and saved on the VNA.
      It needs to set the VNA to CW mode and single sweep.
  -- Trigger single sweep and wait for it to complete
  -- Fix trace definitions
  -- Fix scpi command for VNA sweep mode
  -- Frequency and VNA config file are new parameters in .json file

- Improve plotting
  -- Plot output changed to pdf
  -- CSV file and plot file have the same base name
  -- Make showing the plot a command line argument.
     The pdf file is always created.

- Add status printout during stable measurements

VNA_dummy returns string of measurments as per trace

Features:
-simulated_temperature and simulated_humidity changes as per virtual_time
-plotting function now plots two subplots for temperature, humidity and magnitude,phase with respect to equilibrium_indicator
-Now VNA_dummy doesn't have simulated_measurement_string
-get_measurement_string function now returns string of measurements(magnitude and phase)as per trace instead of simulated_measurements_string

virtual sleep is calling the simulation also for VNA_dummy

Features:
-VNA_dummy and chamber_dummy uses simulated_values from shared_simulated_state
-now climate_chamber_dummy, VNA dummy, Shared_simulated_state has single instance of itselfs
-simulation of climate_chamber runs by virtual_time
-simulation of VNA now runs by virtual_time

Bug_fixes:
-shared_simulated_state_file used in chamber_dummy and VNA_dummy to solve Circular import problem

Working equilibrium_indicator for phase and magnitude

Feature:
- All parameters has stored in seperate json_file
- Phase is in degree, magnitude is in DB
- prototype script has seperate functions for data reading and data writing from chamber and VNA
- prototype script has 5th flag to show all_measurements are stable
- prototype script has seperate class for measurement_data
- Now Equilibrium indicator works for all five flags(temperature_stable, humidity_stable, magnitude_stable, phase_stable, measurements_stable)
- If measurements are not stable it reapits measurements while rading data
- Close chamber correctly even after exceptions

Bug_fixes:
-Now each plot has its legend
-fix stop condition of stability loop

First version with dummies

Features:
- Introduce dummies for the climate chamber and the VNA
- Use localhost instead of the real host name to use the dummy
- Make the 'read_monitor' function more realistic in chamber dummy
- Equilibrium indicator is an integer number representing a bit field
- Prototype script can use the vna dummy
- make prototype script interruptible
  -- <ctrl><C> now gravefully quits and closes the socket properly

Bug-fixes:
- is_temperature_reached and is_humidity_reached work with real chamber

First complete version of the prototype script

- Waits for chamber to reach target point
- Waits for a "soaking time"
- Reads the VNA

Includes equilibrium indicators for temperature and humidity. Phase and magnitude indicators missing. It is just assumes that the soaking time is lonng enough.

First working version of the prototype script

- read and set humidity and temperature
- read S-parameters
- measurments sequence from config file