for safety image v1.0 #14
#14 safety image
copy shared note must copy images
paste image when edit/add shared note
attachment feature #10
#10 #14 [ok]

add attachment feature,
1) upload, delete,
2) link attach into content (include tinymce & markdown)

markdown-editor.js add insertLink function to add link into markdown
content, usage:
MarkdownEditor.insertLink(link, title)

paste plugin edit for safety image
#10 #14
Merge branch 'develop-feature'