v0.1.0

Skip archives that aren't on disk when importing Morrowind.ini

A player's game refused to start because PC_Data.bsa, a Tamriel_Data
archive, was missing, even after they removed their mods and reinstalled
Morrowind and OpenMW. Steam Cloud keeps a copy of Morrowind.ini, so the
fresh install got back the old modded ini. The setup wizard then ran the
ini importer, which copied every archive listed in the ini's [Archives]
section into openmw.cfg without checking that the file exists. The engine
refuses to start when an archive listed in openmw.cfg is missing.

The importer already skipped plugins that it couldn't find. It now does
the same for archives, and prints a warning for each one it skips. It
looks in the same folders as the plugin check: the cfg file's data
folders and the Data Files folder beside the ini. It matches names
regardless of case, using Files::Collections as the engine does, so a
Linux install doesn't lose an archive whose name differs only in case.

Morrowind.ini itself is only read, never written.