Relates to issues containers#183, containers#348, containers#467

Merge branch 'boxhome' of github.com:onuruluag/toolbox into boxhome
Added optional boxhome argument to create command.
Boxhome is concatenated with homedir in order to be under host's home dir.
Homedir is still mounted. No worries.
Being under host's home enables easy file sharing, and prevents privilage issues.
When boxhome argument is not given, system works as before (uses user's home dir):

src/cmd/create.go

@@ -97,6 +97,12 @@ func init() {
 		"",
 		"Create a toolbox container with a different home path than the host.")
 
+	flags.StringVarP(&createFlags.boxhome,
+		"boxhome",
+		"b",
+		"",
+		"Create a toolbox container with a different home path than the host.")
+
 	createCmd.SetHelpFunc(createHelp)
 	rootCmd.AddCommand(createCmd)
 }