It now reads everything into a two-dimensional TMap and creates a list of mappings that apply to the current setting.
The constant need for reloading was the main blocker in redesigning how Dehacked strings get inserted. Currently they override everything, but IWAD-based Dehacked text shouldn't block PWAD overrides from PWADs' LANGUAGE lumps and instead be treated as coming from an [en default] block.
This also renames the main block from [enu default] to [en default], because it should be treated as the English default for all English locales and not just make it fall through to the base default as it did before.
# Conflicts:
# src/doomstat.cpp
# Conflicts:
# src/stringtable.cpp
