Fix isValidEncryptionKeyPacket function: access key flags by index
Verify subkey revocation signatures according to: http://www.rfc-editor.org/errata_search.php?rfc=4880&eid=3298
add variable item name in localstore
fix calue access
add description
fix keyring email check
Add getExpirationTime method to Key and SubKey
Merge pull request #169 from openpgpjs/subkey_revocation

Verify subkey revocation signatures according to: RFC4880 Errata ID: 3298
Add unit test for custom localstorage item name
Merge branch 'pr/170'
Add unit tests for getExpirationTime Key method
Merge branch 'key_enh'