Fix issue where `stop` could stopped already stopped timers

Godeps/Godeps.json

@@ -1,6 +1,6 @@
 {
 	"ImportPath": "git.bullercodeworks.com/brian/gime",
-	"GoVersion": "go1.9",
+	"GoVersion": "go1.10",
 	"GodepVersion": "v79",
 	"Deps": [
 		{

timer_operations.go

@@ -112,9 +112,9 @@ func cmdStopTimer(args []string) int {
 			fmt.Println("Error parsing timer id:", err.Error())
 			return 1
 		}
-		tmr, _, err = findTimerById(timerId)
-		if err != nil {
-			fmt.Println(err.Error())
+		tmr = actTimers.Get(timerId)
+		if timerId >= actTimers.Length() || timerId < 0 || tmr == nil {
+			fmt.Println("Error finding timer with id:", timerId)
 			return 1
 		}
 	}