Temporarily reintroduce integer values for Facing (and possibly Axis)

[dktapps]

Deleting these made it much more of a hassle to do migration work on PM, so I ended up abandoning it.

It would be preferable if, as an intermediary step, the values were brought back as deprecated, so that the core code can be modernized without being forced to completely get rid of value dependencies at the same time.

[dktapps]

I also found various issues around needing to use Facing as array keys, which pretty much just forced the use of Facing->name as the key. I forget the other issues that popped out of this, but they weren't great.