Merge branch 'master' into master

Author: vmmp159

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/StaticHtmlGenerator.java

@@ -182,7 +182,7 @@ public void preprocessSwagger(Swagger swagger) {
         Info info = swagger.getInfo();
         info.setDescription(toHtml(info.getDescription()));
         info.setTitle(toHtml(info.getTitle()));
-        Map<String, Model> models = swagger.getDefinitions();
+        Map<String, Model> models = swagger.getDefinitions() != null ? swagger.getDefinitions() : new HashMap<String, Model>();
         for (Model model : models.values()) {
             model.setDescription(toHtml(model.getDescription()));
             model.setTitle(toHtml(model.getTitle()));