- It can handle negative numbers up to -99
	- It can hadle 0
	- It can handle positive numbers up to 999
	- It automaticly add °C at the end
	? Rename to set_temperature(int16_t temperature)
	? Consider and handle numbers smaller than -99 and taller than 999

Reworked for new library display.h for driving 7-segment display.
Removed all implementations of old FourTimesEihtSeg.h

Next time files instances must be removed!!

Power level is calculated only when needed

Temperature measuring isn't working!!

	- methods:
			- ini() - variables needs inicializing outside constructor
			- handler() - determine button press with lenght and call the
appropriate function 
			
Add function oven_ini() in main.cpp

	- method irq_handler() - provides led controling in interrupt
	-> pec.led.error()

	- Add methods:
					- uint16_t get_adc_value()
					- void set_adc_value(uint16_t)
	
	- Add namespace reflow_oven
		- Add enum baking_state

Instance led moved to reflow_oven_control class
Add method for getting value of power_leve - uint8_t get_power_level()

Reworker method get_triak_state() - now it reads real state
Updated usart.h to newes version from VLKVT project
(transmit_binaryxx())

 - New variable real_temperature_round - contains temperature in entire
degrees
 - Variable real_temperature contains tempereture with 2 digits
precision (2119 -> 21.19°C)
 - Method get_real_remperature() returns real_temperature_round

Temporaly disabled display_render() - it's messing up ADC conversion!

But it didn't work with display, need FIX!