When the `Info.plist` doesn’t exist in filesystem (e.g. because it’s in `.gitignore`)
xcodegen generates the file but doesn’t add it to the `xcodeproj`. Only when
`xcodegen` is executed a second time it is included.
This changes the order of generation of these files to first generate the
plist and then the project.
This allows parameterizing templates. Also change
placeholder syntax to `${placeholderName}` also for
existing placeholders `$target_name`and `$platform`
and generate warnings when using the old placeholder
syntax.
yonaskolb
Tom Quist