Add homepage to package.json

[wvl]

Can you please add the following keys to the package.json?

{
  "homepage": "https://github.com/weaver/node-mail",
  "repository": { "type": "git", "url": "https://github.com/weaver/node-mail.git" },
  "bugs": { "url": "https://github.com/weaver/node-mail/issues" }
}

At least the homepage would be great, that way people can find the repo simply by doing npm docs mail.

Thanks for the library.