* kill process tree using syscall on windows & cleanup (#80)
* kill process tree using syscall on windows & cleanup
* use job api
* add error check for cmd.Start
* modularize monitor, reduce init usage
* replace slices with sort
* update gopsutil & other dependencies
* refactor(pty): switch to using interface
for better flexibility (although may not be useful)
* chore: reduce error messages
* delete redundant messages
