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

wc.sym

@@ -1,50 +0,0 @@
-00000000 wc.c
-00000000 ulib.c
-00000000 printf.c
-00000490 printint
-00000900 digits.0
-00000000 umalloc.c
-00000e00 freep
-00000e04 base
-00000180 strcpy
-00000540 printf
-0000047b greeting
-000003a0 memmove
-0000044b mknod
-000002a0 gets
-0000041b getpid
-00000770 malloc
-0000042b sleep
-000003e3 pipe
-00000473 getch
-00000443 write
-00000403 fstat
-000003f3 kill
-0000040b chdir
-000003fb exec
-000003db wait
-000003eb read
-00000453 unlink
-000000a0 wc
-000003cb fork
-00000423 sbrk
-00000433 uptime
-00000be8 __bss_start
-00000240 memset
-00000000 main
-000001b0 strcmp
-00000483 shutdown
-00000413 dup
-00000c00 buf
-00000310 stat
-00000be8 _edata
-00000e0c _end
-0000045b link
-000003d3 exit
-00000360 atoi
-00000210 strlen
-0000043b open
-00000260 strchr
-00000463 mkdir
-0000046b close
-000006e0 free