[x] Make sure your project contains a @SUBJECT-ID action-tagged field
[x] Make sure your subject ID field works properly on default settings (i.e. it is set & displayed according to the layout defined in the documentation, including the prefix and the zero left padding)
[x] Customize all Automatic Subject ID settings
[x] Make sure your subject ID still works as expected
Solves #6.
Review steps:
@SUBJECT-ID
action-tagged field