Redesign plugin interface with editor and renderer and language and so on.
 - Extract video plugin from base code
Merge branch 'develop' into feature/extract-video-plugin

Conflicts:
	dist/summernote.js
	dist/summernote.min.js
	src/js/editing/Editor.js
erra: dettach to detach
Merge pull request #680 from HackerWins/feature/extract-video-plugin

Redesign plugin interface and extract video plugin from base code.