Simplify Forego.startProcess (#79)

* Remove unnecessary return

* Simplify method Forego.startProcess

We need to call f.teardown.Fall() only when a process has finished
and restart is disabled.

When f.teardown.Barrier() is closed, it’s unnecessary to call
f.teardown.Fall() because we know the barrier is already closed.

* Don’t wait twice on finished

The select has two cases. In the first case, we wait on finished.
We don’t need to wait on finished a second time since we already know
that finished is closed. This is the reason why we moved the defer statement
at the beginning of the second case.

* This goroutine doesn’t need to block until the process has finished

start.go

@@ -163,17 +163,12 @@ func (f *Forego) startProcess(idx, procNum int, proc ProcfileEntry, env Env, of
 	go func() {
 		defer f.wg.Done()
 
-		// Prevent goroutine from exiting before process has finished.
-		defer func() { <-finished }()
-		if !flagRestart {
-			defer f.teardown.Fall()
-		}
-
 		select {
 		case <-finished:
 			if flagRestart {
 				f.startProcess(idx, procNum, proc, env, of)
-				return
+			} else {
+				f.teardown.Fall()
 			}
 
 		case <-f.teardown.Barrier():