Header consts
- Add header constants (thanks @ThomasLandauer), see updated readme for examples and https://mail-mime-parser.org/api/1.3/classes/ZBateson.MailMimeParser.Header.HeaderConsts.html for full API
- Updated mb-wrapper to 1.0.1 to address an issue with CP1258 (new version of mb-wrapper fixes #141)
- Fix subject headers with consecutive spaces #127
- Don't handle tokens in AddressBaseConsumer #148
- Add E_USER_DEPRECATED notices to deprecated calls