[gmime] Created tag 2.4.21

[Jeffrey Stedfast <fejj src gnome org>]

The unsigned tag '2.4.21' was created.

Tagger: Jeffrey Stedfast <jestedfa microsoft com>
Date: Tue Feb 7 12:09:24 2017 -0500

    Tagged for 2.4.21

Changes since the last tag '2.4.20':

Jeffrey Stedfast (15):
      Updated tutorial
      Signature verification w/o writing to disk
      fixed comment
      Fixed all signer_get_* functions to take const signer
      Fixed multipart_signed_verify to always set err on error
      Updated copyright
      Updated reference docs
      Updated docs
      Handle more malformed addresses
      Fixed README
      Fixed INSTALL file
      Updated INSTALL file
      Removed INSTALL file from git repo
      Updated .gitignore
      Bumped version to 2.4.21