Conflict with Scheduler on Due

Referenz: http://arduino.cc/forum/index.php/topic,157950.0.html

Background: In the constructor u8glib calls the Arduino delay() procedure, 
which in turn calls yield(). However, when using Scheduler.h it might not work 
because yield() has not been setup correctly

Workaround: u8glib should not call delay, but delayMicroseconds()

in u8g_delay.c replace

void u8g_Delay(uint16_t val)
{
    delay(val);
}

with

void u8g_Delay(uint16_t val)
{
    delayMicroseconds((uint32_t)val*(uint32_t)1000);
}

Original issue reported on code.google.com by olikr...@gmail.com on 6 Apr 2013 at 8:08

stansip / u8glib

Conflict with Scheduler on Due #155