Replace a couple of load/store actions with new APIs that do so
asynchronously (using indexeddb underneath, via emscripten APIs.)
Required restructuring how app starts. More changes to come. The idea is
to replace wordlist storage: this'll keep 'em smaller and not require
conversion to string.
As a p.o.c., load the built-in wordlist into storage once, and
thereafter use it from there rather than as a file. Now it can go away
and a wordlist for the user's locale be downloaded and stored instead.
I'm heading toward being able to know what all the games are by how
they're stored in a xplatform way. This is a start. Adding a second key
to storage, and looking at grouping everything where one key or the
other matches.