[Discussion] Mark SED-ML files as "master" in OMEX manifests

[jonrkarr]

Currently, no files are marked as "master" in OMEX manifests. In our experience, the "master" attribute is being used inconsistently across the field. To reduce this confusion, we are encouraging this to be generalized in a future version of the manifest format. Until then, we are encouraging SED-ML files to be marked as "master" (master="true").

Identified by @bilalshaikh42