Features:
* #1053 - Ruby 2.4.0 compatibility. Fixnum+Bignum unified as Integer. (peterkovacs)

Bugs:
* #605 - Fix Mail::Address#name for nil addresses (peterkovacs)
* #1003 - Fix decoding some b encoded headers on specific rubies that don't account for lack of base64 padding (kjg)
* #1023 - Fix double-quoting in display names. (garethrees)