1. There is no reason for cdwrap to be templated, it can simply store
the factory function reference instead.
2. Marks overriden virtual functions as `override` instead of `virtual`.
libmpq is a much simpler alternative to StormLib for reading MPQ archives.
We use our own fork of libmpq: https://github.com/diasurgical/libmpq
Impact:
* DevilutionX is now a lot more portable. Unlike StormLib, libmpq only
needs platform-specific code for Windows.
* Locks around file access **removed** (instead we duplicate the file descriptor for streamed audio only).
* RAM usage is **300 KiB** lower than StormLib.
* Stripped release linux_x86_64 binary is **32 KiB** smaller.
* Amiga build now hangs instead of crashing.
Gleb Mazovetskiy
Anders Jenbo
staphen
Xadhoom
Guillaume Roche
Marlon Beijer
Xadhoom