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

defs.h

@@ -22,6 +22,11 @@ void            cprintf(char*, ...);
 void            consoleintr(int (*)(void));
 int             consoleget(void);
 void            panic(char*) __attribute__((noreturn));
+int             newconsole(void);
+int             switchtoconsole(int consoleindex);
+int             closeconsole(int consoleindex);
+int             getcurrentconsoleindex(void);
+void            clearscreen(void);
 
 // exec.c
 int             exec(char*, char**);