currentUILevel is now primaryLevel.
For ZScript, currentVMLevel was added. This is also exported as 'level' and will change as needed.
This also means that no breaking deprecations will be needed in the future, because in order to sandbox a level only 4 variables need to be handled: level, players, playeringame and consoleplayer.
The remaining global variables are not relevant for the level state.
The static 'level' has been mostly removed from the code except some places that still need work.
LevelLocals on the left side of.a function call will now always be remapped to 'Level', which will either remap to the same-named instance variable or the global deprecated one.
In a few degenerate cases where there is a conflicting local variable named 'level' it may error out but that is unavoidable here but this is very unlikely.
- allow treatment as one-character string constants as character constants. This became necessary because name constants already use single quotes and are much harder to repurpose due to a higher degree of ambiguity.
- fixed: protected methods in structs were not usable.
Note that this completely disables the newly added keywords 'play' and 'ui' for unversioned code to allow using them as identifiers as I have found at least one mod that uses a variable named 'play' that would have been rendered broken otherwise.
This also disables many ZScript only keywords for other parsing jobs.
