reintroduce lowmem texture atlas for the qt build

added comiled lowmem version with ASCII only
add lowmem atlas, this is the automatically generated file from the atlastool
remove nofont generated *.cpp  and only add the first 127 bytes of ASCII to the lowmem generation configuration

For Qt only: using platform independent usleep and load lowmem atlas map
Merge pull request #4571 from Bigpet/lowmem_atlas_minimize

reintroduce lowmem texture atlas for the qt build