Merge pull request #14 from lazlolazlolazlo/master

Start with label localization 
Adds signature verification, fixes #8
Merge pull request #15 from lazlolazlolazlo/master

Use roundcube template system for key manager, fixes #15
Adds preview action trigger (thanks Thomas Bruederli)
Removes finished TODOs
Uses rcmail.display_message() to inform about signature verification
Replaces cookie passphrase store with sessionStorage

Fixes #19
Cleanup
Binds encryptAndSend() to beforesend instead of Larry dependant rcmbtn114

Fixes #16
Fixes incorrect escapation
Adds bcc and cc to recipients match (fixes #17)

Matches recipient addresses with a regex solution (which will always be broken because that's just how emails work) (fixes #18)
Merge with upstream