* Adds test support for flow difference
* New support for FunctionTypeAnnotation
* New support for ObjectTypeAnnotation
* New support for MixedTypeAnnotation
* Add the type property to typedef comments
When using Flow type aliases we didn't add the `type` property
to the JSDoc comment for the inferred `typedef`.
Fixes#516
* Rename files and update test expectations
Also:
* Fixes many issues in the default theme
* Moves the default theme from default-theme to default_theme
* Creates a new, robust linker infrastructure that will support
bare links
* Replaces slugg with github-slugger
* Outputs unknown types as Any. Fixes#451