In-memory extension data

[jamierocks]

Effectively the same as kashike implemented in heart.

There should be extension data (provided by lorenz) for manually toggling a mapping as de-obfuscated - specifically useful in Survey's EnumNameMapper (in case they are weren't obfuscated, prevents another mapper giving them another name thinking they weren't deobf'd).

[jamierocks]

Implemented with c097a23.