DynamicTemplate::generateManifest
Generate the normalised manifest array for this template. If there is a file within this folder called MANIFEST, then use that. Otherwise generate a default manifest based on what is present in this folder.
Note: if there is a file present, but it doesn't parse, the default logic is used instead. The manifest is assumed to have been checked for errors at the time it's loaded, and should be dealt with then.
Signature
public function generateManifest()