BREAKING CHANGE: various APIs have been removed/added to simplify TS
compatibility.  `hasLikelySynced` event has been dropped, and only
_some_ pouch methods are attached directly to Pouchy instances with
strong typings.  Typescripts mixins interface is limited and cumbersome
to proxy a full API (PouchDB::Dababase onto Pouchy), especially with overloads,
thus, a subset of interfaces was carried over.  It should meet 95% of
use cases.  The user is otherwise encouraged to drop to
`pouchyInstances.db` as necessary.