Fixed|WorldSystem: Wrong MapInfo used when changing map (typo)
Fixed|libcommon|Doom|Doom64: Build errors

Fixed a number of cases of illegal const usage and references to
temporary values.

It is sad that MSVC allows these to compile.
Merge branch 'master' into gamemenu-rebuild-on-reset
Refactor|libcommon: Game menu list widgets have ownership of list items

As of this commit, all game menus are constructed dynamically using
memory allocated from the heap rather than the Zone. All allocated
memory is freed when Hu_MenuShutdown() is called.

Todo: Cleanup.