warning for package names with spaces or auto add dashes

[debs-obrien]

When creating your app if you use a package name with spaces you don't get the warning until you have answered all the questions and then are left frustrated as your app can't be built because you added a name with a space which is not allowed. this warning should come right at the very moment you enter or better still dashes added automatically so it is something you don't have to deal with.