Changed the check rate, uncommented tone calls

Had to change NewPing library (NewPing.cpp line 214):
// commented out so it doesn't conflict with Arduino tone library
//#if defined (__AVR_ATmega32U4__) // Use Timer4 for ATmega32U4
(Teensy/Leonardo).
//ISR(TIMER4_OVF_vect) {
//#else
//ISR(TIMER2_COMPA_vect) {
//#endif
// if(intFunc) intFunc(); // If wrapped function is set, call it.
//}