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

rm.sym

@@ -1,48 +0,0 @@
-00000000 rm.c
-00000000 ulib.c
-00000000 printf.c
-00000390 printint
-000007f4 digits.0
-00000000 umalloc.c
-00000aac freep
-00000ab0 base
-00000080 strcpy
-00000440 printf
-0000037b greeting
-000002a0 memmove
-0000034b mknod
-000001a0 gets
-0000031b getpid
-00000670 malloc
-0000032b sleep
-000002e3 pipe
-00000373 getch
-00000343 write
-00000303 fstat
-000002f3 kill
-0000030b chdir
-000002fb exec
-000002db wait
-000002eb read
-00000353 unlink
-000002cb fork
-00000323 sbrk
-00000333 uptime
-00000aac __bss_start
-00000140 memset
-00000000 main
-000000b0 strcmp
-00000383 shutdown
-00000313 dup
-00000210 stat
-00000aac _edata
-00000ab8 _end
-0000035b link
-000002d3 exit
-00000260 atoi
-00000110 strlen
-0000033b open
-00000160 strchr
-00000363 mkdir
-0000036b close
-000005e0 free