Improve readme

[lencioni]

This pull request contains a couple of small improvements to the readme:

• hard wrap at 80 characters for readability
• fix incorrect path when talking about components.js

[zpao]

Can you sign the cla (https://code.facebook.com/cla)?

(I personally don't care for the 80 character change BUT I'll let @JakubMal make that call)

[facebook-github-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file. In order for us to review and merge your code, please sign up at https://code.facebook.com/cla - and if you have received this in error or have any questions, please drop us a line at cla@fb.com. Thanks!

[jtmalinowski]

Hi, if https://github.com/rails/rails can be of any indication, they don't hard wrap in their README.md, or rather wrap a bit, but it looks like they don't care, also I looked at a few other gems, and they don't wrap too, btw I think any text editor should be able to do this for you.

You are right about the link, so it would be best if you could just remove b833641 and we're ready to go!

Thanks!

[lencioni]

Sure thing, all done.

[jtmalinowski]

What we need yet is your CLA :) It's kind of ridiculous for a change this small, but I can't help.

[lencioni]

We have submitted the corporate CLA, so we should be good to go there. Let me know if there is anything else I need to do.

[zpao]

I don't see Causes under the organization CLAs. Let me know if it's actually a different name or if I should go bug somebody who works on that tool to make sure it didn't get lost.

[lencioni]

I believe that it was submitted with the company name "Causes". Let me know if any additional information would be helpful.

[zpao]

All good on the CLA front, feel free to merge when ready @JakubMal