Bug fixes and feature adds

Bugs fixed:
- When frequency is set again and rf is off, it was becoming on and display showed off. It is fixed as always looking for isrfonoff variable.
- When interrups started, device become bricked. It is fixed by clearing every interrupt when functions started.
- Temperature calculations were wrong (fahrenheit). Multiplier was integer. Now it is float and corrected. Bug #1 fixed.

Improvements:

- Arduino's analogRead function is very slow for us and it is changed to free running mode and always on. Therefore this gives 2-3 times boost in calculations.
- To be able to make faster and accurate modulations, delay calculations are now in nanoseconds. This gives internal modulation frequency precision.
- Now external modulations are mocuh faster. They precalculated in 7 bits. So in infinite loop, it only get adc value and use lookup table to find pre calculated value. This made external modulation frequency limit 100 times higher.
- RFSA (Step attenuater) was using 5 MHZ SPI clock. It is doubled.
- Internal modulation calibrations are corrected.
- Now every modulation can be sweeped. It was only availabe in Internal AM and FM.

Version v1.0.7