Work-around 8.7.7 regression

Bug: https://bugzilla.zimbra.com/show_bug.cgi?id=107013
Fix: Zimbra/zm-ajax#5

move some code

fix typo

update purify.js

add new version

add release 2.6.6

implement key expiration time

update version number

add version 2.6.3 catalan i18n

replace stringencoding with upstream up-to-date version

fix: https://github.com/Zimbra-Community/pgp-zimlet/issues/208