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

init.sym

@@ -1,49 +0,0 @@
-00000000 init.c
-00000000 ulib.c
-00000000 printf.c
-000003f0 printint
-00000870 digits.0
-00000000 umalloc.c
-00000b24 freep
-00000b28 base
-000000e0 strcpy
-000004a0 printf
-000003db greeting
-00000b1c argv
-00000300 memmove
-000003ab mknod
-00000200 gets
-0000037b getpid
-000006d0 malloc
-0000038b sleep
-00000343 pipe
-000003d3 getch
-000003a3 write
-00000363 fstat
-00000353 kill
-0000036b chdir
-0000035b exec
-0000033b wait
-0000034b read
-000003b3 unlink
-0000032b fork
-00000383 sbrk
-00000393 uptime
-00000b24 __bss_start
-000001a0 memset
-00000000 main
-00000110 strcmp
-000003e3 shutdown
-00000373 dup
-00000270 stat
-00000b24 _edata
-00000b30 _end
-000003bb link
-00000333 exit
-000002c0 atoi
-00000170 strlen
-0000039b open
-000001c0 strchr
-000003c3 mkdir
-000003cb close
-00000640 free