Fix #158: GD alpha detection + Color::isOpaque are broken
Merge pull request #310 from romainneutron/fix-158

Fix #158: GD alpha detection + Color::isOpaque are broken
Update Changelog
Update API doc
Refactor metadata to ease writing custom reader
Add metadata documentation
Move web optimization filter tests to the correct namespace
Add autorotate filter based on exif metadata
Merge pull request #317 from romainneutron/metadata-docs

Add metadata docs, ease the process of writing custom readers
Update API docs
fix typos
Merge pull request #318 from romainneutron/autorotate-filter

Add autorotate filter based on exif metadata