Change editor button design.
Adjusted hover effect on grey button to be wcag comp.
Merge branch 'master' into api-1.1
Merge branch 'api-1.1' into api-1.2
Merge branch 'api-1.1' into api-1.2

Conflicts:
	library.json
Merge branch 'api-1.2' of github.com:h5p/h5p-editor-course-presentation into api-1.2

Conflicts:
	library.json