Support for relative links now in place #73

Tests all passing, runs super fast, pulls in every single DigitalOcean spec and parses it. There may be some issues deeper down in the models, but for now high level tests all pass.

document_test.go

@@ -113,7 +113,7 @@ paths:
 	assert.NoError(t, err)
 
 	v3Doc, docErr := doc.BuildV3Model()
-	assert.Len(t, docErr, 1)
+	assert.Len(t, docErr, 2)
 	assert.Nil(t, v3Doc)
 }