NewTone / APRS / SD Timer Conflicts

[tcarissimo]

This currently utilizes the NewTone library to control the Piezo speaker/alarm. This library utilizes Timer 1 on the Arduino which may be conflicting with our other timer operations that also utilize the same timer for APRS and/or SD card writes. APRS operations may also be conflicting with SD card operations. Need to investigate this for resolution.

As far as I'm aware:

NewTone = Timer 1
APRS = Timer 2
SD Card = SPI (??) using digital pins 10, 11, 12 & 13

Not sure how the SD card is running off of pins 10, 11, 12 & 13 via Arduino Mega. Seems like this shouldn't work, but somehow I got it to work and I don't remember how. Software SPI? Maybe Magic? Who knows....?