marked instead of draft-js #42

I am thinking of removing our dependency on draft-js by marked

Reasons:

• Marked is light weight & fast than draft-js
• low-level compiler for parsing markdown without caching or blocking for long periods of time
• Easy to use.
• Can modify it as per our needs. This is complex in draft-js.
• Have more downloads than draft-js.
• Used by Atom text editor for it's markdown preview.

We can easily integrate it with Reactjs.

Resources

• used by Atom text editor (see in package.json) : https://github.com/atom/markdown-preview
• marked : https://www.npmjs.com/package/marked