Resolves output file paths.

Sets the output path for files that are about to be written to disc and calls update() on the file so that files assigned a seal function may update the file content buffer.

ResolveFile.prototype.sources(file, context)

Resolves the file output path and file content.

If the file has already had an output path set it is assumed to be a path relative to the output directory and modified to include the output directory in the file path.