WebAssembly bindings for [edtf_core] — the same validator the database
runs, compiled for JavaScript. The app imports this in place of edtf.js.
Exported API (JS names):
isValid(input)→booleanlevel(input)→0 | 1 | 2 | -1(-1 = invalid)canonical(input)→string | undefined(spec-preferred form)parse(input)→ JSON string of a [Summary] orundefinedrelation(a, b)→ JSON string of a [RelationSummary] orundefined