Added declaration files (#76)

* Added declaration files

still not tested

* Added declaration to package Json

* change folder for declaration

* added joi deps

lib/index.d.ts

@@ -0,0 +1,41 @@
+// Type definitions for express-validation
+// Project: https://github.com/andrewkeig/express-validation/issues
+// Definitions by: Fabian Gutierrez <https://github.com/fega>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+/// <reference types="node" />
+import { RequestHandler } from "express";
+import * as Joi from "joi";
+interface ValidatorField {
+  [key: string]: any;
+}
+interface Validator {
+  body?: ValidatorField;
+  params?: ValidatorField;
+  query?: ValidatorField;
+  headers?: ValidatorField;
+  cookies?: ValidatorField;
+  options?: {
+    allowUnknownBody?: boolean;
+    allowUnknownHeaders?: boolean;
+    allowUnknownQuery?: boolean;
+    allowUnknownParams?: boolean;
+    allowUnknownCookies?: boolean
+  };
+}
+
+declare function validate(validator: Validator): RequestHandler;
+declare namespace validate {
+  export class ValidationError {
+    errors: Messages[];
+    status: number;
+    statusText: string;
+    message: "validation error";
+
+  }
+  interface Messages {
+    message: string;
+    types: string;
+  }
+}
+
+export = validate;