Real fast ramped auto repeat

[GoogleCodeExporter]

I was testing the auto repeat code example and I figured out that it works 
really well when setting small values like 1 to 10. I'm trying without much 
success to make it usable when setting larger values (1 to 999). I tried to 
replace auto_repeat_first_delay and auto_repeat_repeat_delay with lower values 
but still slow for adjusting larger numbers. Any idea on how to achieve this?

Since I'm using the AVR/U8G version, I had to create my millis() function using 
timers:

ISR(TIMER3_COMPA_vect)
{
    timer3_millis++;
}

unsigned long millis()
{
    unsigned long millis_return;
    millis_return = timer3_millis;
    return millis_return;
}

Original issue reported on code.google.com by [email protected] on 10 Jul 2014 at 12:02