add console driver.
add kernel page table
load cr3 and enable page
for test only
del tst
add frame list
load user program
run user programm
switch to user mode and run user program
add keyboard and timer driver
add system call
syscall print
split trap code
delete sublime file
delete sublime files
code refactor
code refactor
add mem allocator, list, spinlock; make malloc function thread safe.
add schedule(not working yet)
refactoring trap handling