graceful shutdown

[endel]

Fixes #457

I noticed when hitting Ctrl-C, this block of code was never called, due to the main process being terminated:

ts-node/src/bin.ts

Lines 59 to 67 in 1d630f9

	proc.on('exit', function (code: number, signal: string) {
	process.on('exit', function () {
	if (signal) {
	process.kill(process.pid, signal)
	} else {
	process.exit(code)
	}
	})
	})

By creating a trap to SIGINT, the main process will be closed only after the child one does.

[coveralls]

Coverage remained the same at 76.826% when pulling 9051e84 on endel:issue-457 into 1d630f9 on TypeStrong:master.

[coveralls]

Coverage remained the same at 76.826% when pulling 9051e84 on endel:issue-457 into 1d630f9 on TypeStrong:master.

[coveralls]

Coverage remained the same at 76.826% when pulling 2b94f36 on endel:issue-457 into 1d630f9 on TypeStrong:master.

[stelcheck]

The issue is that while in terminal this will work, IIRC it won't properly propagate signals when daemonized.

[blakeembrey]

Should be closed with #419, but please let me know if it doesn't!