During long lasting moves of a delta machine neither the temperatures are maintained nor buttons checked nor ... .
The fix is to call 'manage_heater()' and 'idle()' every now and then in the loop where the move is segmented. 
The code is abot the same as in G2_G3 wher we had the same problem with too large circles lasting too long.
Fixing #7510

Travis fix - only allow ultralcd_st7920_u8glib_rrd_AVR.cpp to compile when ST7920 selected

Travis is having problems at:  https://github.com/MarlinFirmware/Marlin/pull/8560   

So...   doing a direct commit to get things correct.   Bugfix_v1.1.x does not have this bug.  Nothing needs to be done to that branch.

These changes may need to be warmed over.  I tried to fix things with
the least amount of disruption.   I just wanted to get the bugfix_v2.0.0
branch working for people again.

Previous fix did not work as expected when axeis not homed. It raise Z but never return to original position