fix: add by path (#838)
fix: add by path (#838)

Adds the ability to `add by path` with only the CID. Also works with `/ipfs/` prefixed.

![path](https://user-images.githubusercontent.com/33324750/46214459-28335000-c333-11e8-961c-93c6883984b5.gif)

Closes https://github.com/ipfs-shipyard/ipfs-webui/issues/824.
ipfs/webui,ipfs/webui,ipfs/webui