create basic folder structure
add c module loader
reduce the folder levels
remove the useless Makefile
add C module loader
re-organize folder structure
add install target rule and add flib links
update LICENSE
add a comments for Makefile
refine Makefile
add a simple scheduler
get clear of the relationship of scheduler, io and io_bridge
1. add sk_assert and sk_io_bridge
2. refine scheduler and io logic
write the logic of starting schedulers
adjust file location
add main_sched and worker_sched
refine sk_io and sk_io_bridge
refine main and scheduler
set up io_bridge
refine sched, event and add ptos