New Features:
- Removed IS_UNICODE (PHP6) support
- Removed support for PHP <5.3.3
- Timestamps encoded according to https://www.w3.org/TR/NOTE-datetime
Bugs Fixed:
- Various missing free calls (remicollet, bd808)
- Fix parameter parsing for yaml_emit_file
- Fix callback handling for yaml_emit_file
- Fix result of tag callback to be copied to aliases (ranvis)
- #71696 Bad datetime management