Updated to VirtualWire 1.13
VirtualWire: Add support for Digispark

Digispark uses ATtiny85 which has only an 8bit timer.  Added
utility function to deal with calculating the CTC match value
and prescaler value.  Implemented use of utility function for
both Arduino and Digispark code.

Signed-off-by: Chris Evich <chris-arduino@anonomail.me>
VirtualWire: Remote extranious whitespace

Signed-off-by: Chris Evich <cevich@redhat.com>