[WO-298] integrate openpgp.js v0.5.0
Merge pull request #40 from whiteout-io/dev/openpgp_0.5

[WO-298] integrate openpgp.js v0.5.0
[WO-297] setting a passphrase is optional
Login to IMAP (appcontroller.onConnect) after show mail-list
use dummy folders on first time login until first sync
Fix listing imap folder onConnect
allow no passphrase on keygen
remove key export dialog after keygen
Fix show messages on initial login/folder-sync