Merge branch 'release/1.3.0' into develop
Set next snapshot version
docs
docs
docs
Add attribute optional to group tag.
Warn if layout tags are called multiple times per request.
Fail fast if configuration is detected after layout has already been
called.
Support outputting inline styles or scripts before rest of resources.
Replace deprecated body-content type for group tag.
Update xml schema.
Fail fast if local file could not be found.
Move some classes to configuration package.
Set release version 1.4.0
Merge branch 'release/1.4.0'