fix compile warning
fix demotool compile
update pr-downloader
fix #4424
fix #4437: /set GrassDetail X
grassdrawer render fartextures 100% on the gpu w/o a cpu readback
fix compile with old GLEWs
grassdrawer: a modern cpu is able to iterate 32x32 structs w/o any performance cost
fix compile
Merge branch 'develop' into fork-develop