Corrected Thracian crest placement and added a couple more in.

Updated Spartans using the bronze/iron sets from my new units mod.

Hotfix 2: Forgot to re-include Spartan women.

Hotfix for Spartan officer crests. I implemented a much more consistent thematic range, but forgot to change the reference to file.

Standardisation of variantmeshdefinition files to ease future work.
Miscellaneous fixes.