replace panic with log.Fatal

cmd/root.go

@@ -18,6 +18,7 @@ package cmd
 
 import (
 	"errors"
+	"log"
 	"os"
 
 	"github.com/spf13/cobra"
@@ -124,23 +125,23 @@ func update(m *milkDropWindow) (bool, error) {
 func milkbucket(cmd *cobra.Command, args []string) {
 	err := checkStdin()
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 
 	err = sdl.Init(sdl.INIT_VIDEO)
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 	defer sdl.Quit()
 
 	err = validatePresets()
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 
 	m, err := newMilkDropWindow(800, 600, presets)
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 	defer m.destroy()
 
@@ -150,7 +151,7 @@ func milkbucket(cmd *cobra.Command, args []string) {
 	for running {
 		running, err = update(m)
 		if err != nil {
-			panic(err)
+			log.Fatal(err)
 		}
 	}
 }