Previously, the memory for each frame was allocated separately.
Changes it to allocate a single buffer for all the frames.
This has the following advantages:
1. Less bookkeeping overhead in the allocator.
2. Less alignment overhead (allocator results are max-aligned by default).
We can follow this up with a similar treatment for other multi-file
animations.
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
obligaron