v1.2.6

This release fixes an issue where placeholder files were not correctly considered as implicitly depending on the generating file. In particular, when using the image glue file to generate foo.images.js from foo.images.json, the produced hash file foo.images.js.hash would not be produced until foo.images.json was processed. So if other.js imports from foo.images.js which requires the foo.images.js.hash, it would be a race for if foo.images.json happens to finish processing before foo.images.js attempts to read foo.images.js.hash

This update maintains a placeholder graph which is used to correctly mark other.js as depending on foo.images.json in the above example.