Added buffer to the console

Added hotkeys to switch between console buffers and to return to the home one
Added clear screen command
Added debug text outputs to the hello command and when loading sh

stressfs.sym

@@ -1,48 +0,0 @@
-00000000 stressfs.c
-00000000 ulib.c
-00000000 printf.c
-00000450 printint
-000008ac digits.0
-00000000 umalloc.c
-00000b64 freep
-00000b68 base
-00000140 strcpy
-00000500 printf
-0000043b greeting
-00000360 memmove
-0000040b mknod
-00000260 gets
-000003db getpid
-00000730 malloc
-000003eb sleep
-000003a3 pipe
-00000433 getch
-00000403 write
-000003c3 fstat
-000003b3 kill
-000003cb chdir
-000003bb exec
-0000039b wait
-000003ab read
-00000413 unlink
-0000038b fork
-000003e3 sbrk
-000003f3 uptime
-00000b64 __bss_start
-00000200 memset
-00000000 main
-00000170 strcmp
-00000443 shutdown
-000003d3 dup
-000002d0 stat
-00000b64 _edata
-00000b70 _end
-0000041b link
-00000393 exit
-00000320 atoi
-000001d0 strlen
-000003fb open
-00000220 strchr
-00000423 mkdir
-0000042b close
-000006a0 free