ARM: software serial port integration (Tx only)

- be careful charging functionality not tested
- work corectly with baud rate 19200 and lover
===
- TMR2 is used for Tx timing
- ADC for temp is disabled when Tx soft serial is active (maybe timing problem for other functionality)
- some logic are added for enable/disable some funcionality when eternal temp or Tx serial is active (probably not enough)
this function should probably look like this:
{
    flush();
    end();
}