The new Spina-based classes recently introduced made use of a nice

feature we had in Spina 1 where you could reference private methods or

include inline functions in event handlers.
Unfortunately, this was only allowed because these mappings were being

rebuilt for every single instance of every class. Plus, they weren't

accessible outside of those classes, meaning other subclasses couldn't

merge them in.
Spina 2 will be addressing the access/merging limitation by expecting

each of these to be static. Unfortunately, that means we can no longer

specify private methods or inline functions. Instead, we need to revert

back to the earlier approach of passing in strings representing function

names.
This change prepares for that by changing #functions to

private _functions(), and specifying them in the maps. It also

converts some templates that were defined as instance variables to be

static.
The event mappings and some other state will be made static in the

upcoming move to Spina 2.

All unit tests pass.
Also tested along with upcoming changes for Spina 2.
Audited all TypeScript in the codebase, making sure there weren't any

classes remaining that needed to be updated, both for this change and

the final move to static.