Add a "kitchen sink" starter

[KyleAMathews]

It'll serve to introduce / document in a visual/tangible way all documentation & loader options.

Also it'll be a nice integration test.

[bartekus]

Thank you Kyle for inviting me to be part of the Gatsby team!
I'm at the moment swamped with few pressing issue but as I resolve them I'll be increase my focus and contributions to the Gatsby project!

[KyleAMathews]

💯

[KyleAMathews]

Actually working on making this part of the default starter as that's what most people will install first so it should show off many of the capabilities of Gatsby.

[KyleAMathews]

This is fixed with gatsbyjs/gatsby-starter-default#7