[general issue] Null Debug Output from METISSE

[d-maclean]

Description

When using METISSE as the stellar engine, an output file is generated (tracks_log.txt). On recent commits (c. ~#715) I've bee noticing this file fills up with repeated messages like this:

 Input Z is :  1.40000E-03
 Could not find column: ������������������������������� [NUL characters]
�(repeat ...)

This message is emitted by METISSE/src/z_support.f90 in the locate_column subroutine. I'm wondering if this is related to an array length / delimiting error (i.e. we read some strings into an array and somehow end up with a string array member that is all empty).

Expected Behavior

Ideally we should see only the normal output (i.e. metallicity of tracks, names of tracks which are skipped)

Steps to Reproduce

1. Call evolve.Evolve() with metisse as stellar engine and some tracks.