New improved "auto_spi_voltage" logic:

On each boot:
  boot.1: initc will set default spi voltage, spi frequency and the dcdc offset.
  boot.2: if there is no configuration file (/config/advanced.conf)
initc.sh creates it with command "waas -d -o /config/advanced.conf".
The "auto_spi_voltage" is set to "true" in this case because "true" is
its default value.
  boot.3: intc.sh runs waas ("waas -c /config/advanced.conf"). Waas
works in its standard mode (see below).

Standard mode of waas:
 a) read settings from specified config file;
 b) run "die #0 problem" detection code. If the problem is detected -
create file /var/run/.waas_p0;
c) if /var/run/.waas_p0 file exists and "auto_spi_voltage" == true,
then spi_voltage=3.3V;
d) implement all settings;
e) read back running values from device (except for "auto_spi_voltage"
- there is no physical value to be read for it, it is kept the same as
in config file);
f) print out running settings.

Web interface:
  The web mgmmt reads /config/advanced.conf, and presents current
settings on web page, the user changes something and press apply,
which write the new file and once the file have been written, the cgi
executes "waas -c /config/advanced.conf". Waas works in "Standard
mode" here, as specified above.

x) monitor_dcdc monitors die current and once more than 3/4 of dies
are found to be faulty, it executes "waas -f" which sets the spi
voltage the "low default" value. The exact behaviour of the waas in
this "-f" mode is the same as in "Standard mode" with one change in
step c):
 ... (a, b as in Standard mode)
c) if /var/run/.waas_p0 file exists and "auto_spi_voltage" == true,
then spi_voltage=LOW_DEFAULT_VOLTAGE (1.95 V);
... (d,e,f as in Standard mode)