BUGFIXES

BUGFIXES
get address value right: bottom bit is always read/write, so:
 in slave mode: shift value for SSPADD left
 in master mode: choose slave address 0x82 = I2C addr 0b1000001, write

NICETIES
disable serial rx and tx interrupts in slave mode
new ifbit1 and ifbit0 macros

DEBUGGING IMPROVEMENTS
master does not panic immediately before sending address
print calculated SSPADD value via debughf in slow slave mode
a few other "debug" statements
debughf gets nybbles > 0x9 right (!)