pack
Packs a named map of files into a NARC container with a full file name table (FNT).
Keys are slash-separated paths (e.g. "sprites/player.bin"). Files within the same directory are stored in sorted order. The resulting NARC can be unpacked with either unpack (index-based) or unpackNamed (path-based).
Return
A valid NARC byte array with a populated FNT.
Parameters
files
Map of slash-separated paths to file contents.