allow only 4 KiB pages for user programs (less code, better understandable)
fix for svga mode (needs 4MiB page PPN resolution)
removed kill_old_ - should improve situations with lots of dying threads
Merge branch 'master' into next_year_improvements
removed 3 warnings (2 in nonstd.c and 1 in the linker script)
Merge branch 'next_year_improvements'