* reverb/echo is not yet implemented, so there's two stub functions for now.
* RTS needs to be done differently, because the sound engine cannot play raw buffers without any control data.
- hooked up all front ends with a generic message printing function so that common code can access the native message displays. This is needed for consolidation of some input actions which are mostly identical but print messages.
- preparations for a generic message system.
Now this was magnitudes easier than the EDuke menu - NBlood's menu is actually clean and usable code but still nothing compared to a unified menu system.
This was only a crutch to let the input interface work with the original menus.
Now that the one in Blood is gone, all the conditions are no longer relevant. (Shadow Warrior never got far enough to implement this)
This mainly means being able to use the generic font.
This also adds more generalization to the menu sound handling, plus an option to turn menu sound off. This is motivated by the pig sounds which RR uses in the menu.
Not tested yet!
* Added a JSON-based header to the savegames so that the unified menu can read from a common data source.
* moved loading and saving of frontend independent data to the wrapper so that support is automatic.
