Ensure no buffalo deps are updated using buffalo new (#1236)

* Install needed packages if necessary, but don't update them.
* When using dep, skip go get pop and its dependencies, use dep instead.

Fixes #482

generators/newapp/new.go

@@ -33,7 +33,7 @@ func (a Generator) Run(root string, data makr.Data) error {
 	}
 
 	if _, err := exec.LookPath("goimports"); err != nil {
-		g.Add(makr.NewCommand(makr.GoGet("golang.org/x/tools/cmd/goimports", "-u")))
+		g.Add(makr.NewCommand(makr.GoGet("golang.org/x/tools/cmd/goimports")))
 	}
 
 	if a.WithDep {
@@ -43,7 +43,7 @@ func (a Generator) Run(root string, data makr.Data) error {
 			// This step needs to be in a separate generator, because goGet() exec.Command
 			// checks if the executable exists (so before running the generator).
 			gg := makr.New()
-			gg.Add(makr.NewCommand(makr.GoGet("github.com/golang/dep/cmd/dep", "-u")))
+			gg.Add(makr.NewCommand(makr.GoGet("github.com/golang/dep/cmd/dep")))
 			if err := gg.Run(root, data); err != nil {
 				return errors.WithStack(err)
 			}

generators/soda/soda.go

@@ -28,9 +28,11 @@ func (sd Generator) Run(root string, data makr.Data) error {
 	f.Should = should
 	g.Add(f)
 
-	c := makr.NewCommand(makr.GoGet("github.com/gobuffalo/pop/..."))
-	c.Should = should
-	g.Add(c)
+	if !sd.App.WithDep {
+		c := makr.NewCommand(makr.GoGet("github.com/gobuffalo/pop/..."))
+		c.Should = should
+		g.Add(c)
+	}
 
 	g.Add(&makr.Func{
 		Should: should,