model/refactor: change around how requests/stores work.

* move the code around for fun.
* better-name the states vs the "case classes".
* fix some bugs in store default handling.
* move handled/unhandled signals off of OneOfStore.
* add MemoryCacheStore default.
* add OnPageCacheStore default.
model/noop: PageModel should have an empty #_render().
package/noop: bump version to 0.1.2 for republish.
collection/refactor: move collection deserialization to collection.
library/bug: nullcheck on result before trying to instantiate.
varying/refactor: change to just #map() for mapping. soon to spread.
main/noop: export store; move around structure.
application/bug: request state typechecks against type subject.
application/refactor: allow override of app creation in Endpoint.

* useful for eg logging hooks.