Merge branch 'add_embed' of https://github.com/vexus2/medium-editor-insert-plugin into vexus2-add_embed

Conflicts:
	README.md
	dist/css/medium-editor-insert-plugin.css
	dist/js/addons/medium-editor-insert-images.js
	dist/js/addons/medium-editor-insert-images.min.js
	dist/js/addons/medium-editor-insert-maps.js
	dist/js/addons/medium-editor-insert-maps.min.js
	dist/js/addons/medium-editor-insert-plugin.min.js
	dist/js/medium-editor-insert-plugin.all.min.js
	src/js/medium-editor-insert-images.js
	src/js/medium-editor-insert-maps.js