Due to dependencies on initializing some data in app_init it was not possible to cleanly set up the fonts.
This adds a game-side function for loading the entire palettes before starting with the texture data and another one for loading game-side texture data.
This now allows fully setting up the palettes before starting with the textures and to fully set up the textures before reading the .def files.
All this is needed because to properly initialize, the fonts need to be able to access the fully initialized texture state, including replacements and hires substitutions from the .def files.
* moving polymost_voxdraw into polymost.cpp.
* consolidated all remaining voxel code in hw_voxels.cpp. All original Build voxel code is completely gone now, except for polymost_voxdraw, so this got moved out of the build/ folder.
* integrate Blood's voxel init code into the main function.
* some further cleanup was allowed as a result of this, so engineInit is gone now because these parts can now be done outside the games' app_init functions.
