Merges branch 'release/0.3.0' into develop
Adds pluginMeta to validator.

Also adds custom stylesheet support.
Bumps version to 0.3.1
Updateds changelog for 0.3.1
Merges branch 'release/0.3.1'
Merges branch 'release/0.3.1' into develop
Reverse plugin sort order to match Composer.
Bumps version to 0.4.0.
Updates changelog for 0.4.0.
Merges branch 'release/0.4.0'