Add meta object documentation for all rules. Closes #48

[MarkKragerup]

This pull request is an alternative from #61 and closes issue #48 Difference being:

• This one has no merge conflicts.
• This one attempts to do minimal changes to the code beyond adding the meta property for rules.
• This one uses the current markdown documentation rather than the inline comments as source for the descriptions.
  It still has a lot of indention changes, due to the fact that adding the meta property required converting the export into a one level higher object.
• Corrects gramatical errors in the documentation.
• Adds documentation for detect-new-buffer to the readme aswell, as it was missing.

[MarkKragerup]

@nzakas I checked the links and made this PR, as an alternative. If you merge it, issue #48 and PR #61 can be closed.

[nzakas]

Thanks for doing this. Some general notes:

1. When referencing blog posts in the docs, it’s important to indicate what the post is about. I’ve made some suggestions for these.
2. In the meta info, description should be a single sentence without markdown content.
3. meta.docs.url should always be a link to the rule documentation online. If no docs are available, this field can be omitted.
4. It seems like these rules should all be “error” (something bad might be happening here) instead of “suggestion” (an alternate way of doing something).

[MarkKragerup]

@nzakas i corrected all 4 points of feedbacks. The reason i put it as a suggestion instead of an "error" originally was due to the large number of false positives these rules can give. But i have changed it to "error" now, and i think we should rather work on reducing false positives in the rules separately.

[nzakas]

LGTM. Thanks.

[lolgab]

@nzakas When are you planning to release a new version?
This is a great improvement for everyone who uses ESLint programmatically and reads the meta objects.
It also adds the recommended patterns which are very useful.

[nzakas]

@lolgab I'd still like to get through the rest of the PRs and issues before releasing a new version.