Based on #9030

minor edits to force new Travis test (last one timed out)

Update u8g_com_HAL_DUE_st7920_sw_spi.cpp

initial power up display garbage gone

found a few more nasties

Formatting tweaks

correct array initialization & remove test code

Based on #9008

Fix #8901

Now the USB MSD can transfer at 750k/s. Previously, it was 500k/s. I think this is the maximum achievable speed using Sw SPI.

…and show bed level indicator at the position of the [H] icon, when a heated bed exists.

For parity with #8911