Only the .spine or .outline file is sent to the tagging backend
Description of the problem: On triggering the automatic tagging for a .outline file, MaggotUBA only gets the .outline file and not .spine file, and fails to tag the data since it needs the .spine file. Even worse: if a predicted.labels already exists in the processed directory of the tagging backend, this file is taken back by LarvaTagger.jl. Explicit failure is reported only in the case of a fresh model instance.
Steps to reproduce: Open a .outline file, click on "Autotag". To make LarvaTagger.jl reload the wrong file, first open a trx.mat file and click on "Autotag", and then proceed with the steps described before. The UI reloads the trx.mat in lieu of the .outline file.
Expected behavior: LarvaTagger.jl sends both the .spine and .outline files. If the backend fails, no labels file is retrieved.
Proposal: Prior to calling the backend, delete the processed directory just like the raw directory already is. Abstract the data source away from the file, so that all the files are sent to the backend when a data source is composed of multiple files.