Handle SIGINT

Handle SIGINT by stopping the traced program and then displaying a
prompt to the user for commands. If the traced process is not running,
this is a noop.

Closes #30

client/cli/cli.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"os/signal"
 	"strings"
 	"syscall"
 
@@ -47,6 +48,16 @@ func Run(run bool, pid int, args []string) {
 		}
 	}
 
+	ch := make(chan os.Signal)
+	signal.Notify(ch, syscall.SIGINT)
+	go func() {
+		for _ = range ch {
+			if dbp.Running() {
+				dbp.RequestManualStop()
+			}
+		}
+	}()
+
 	cmds := command.DebugCommands()
 	goreadline.LoadHistoryFromFile(historyFile)
 	fmt.Println("Type 'help' for list of commands.")