Make all `read*` functions accept an options object, so that we can add config
options to them later (for #1166). This is necessary so that we can remove the
global `openpgp.config`, which doesn't work that well when importing
individual functions.
Furthermore, merge `readMessage` and `readArmoredMessage` into one function,
et cetera.
- `openpgp.generateKey` now expects `userIds` in object format
(strings are no longer supported)
- Remove `util.parseUserId` and `util.formatUserId`
- Replace `UserIDPacket#format` with `UserIDPacket.fromObject`
- Changes `openpgp.generateKey` to accept an explicit `type` parameter,
instead of inferring its value from the `curve` or `rsaBits` params
- Introduces `config.minRsaBits` to set minimum key size of RSA key generation
- Remove the boolean return value of various internal functions that throw on
error (the returned value was unused in most cases)
- Update and fix type definitions
