Remaining DL_MESO issues - 3 to go

[LonelyCat124]

• [x] Modularise read and writes so we don't mess up the global namespace.
• [x] Switch from strcmp to strncmp to match exactly the DL_MESO fortran string comparisons
• [ ] Check the outputs are correctly laid out / fix them to be the same as Fortran if required.

These issues have not been investigated in the branch, and are important to complete the dl_meso feature set in the future.