Fixed declaration and tests

gulp-help-doc/gulp-help-doc-tests.ts

@@ -13,7 +13,10 @@ import usage = require('gulp-help-doc');
  */
 gulp.task('demo', function() {});
 
-var logger = {
+let logger: {
+    output: string,
+    log(msg: string)
+} = {
     output: '',
     log: msg => logger.output += msg + '\n'
 };

gulp-help-doc/gulp-help-doc.d.ts

@@ -5,11 +5,12 @@
 
 /// <reference path="../node/node.d.ts" />
 /// <reference path="../gulp/gulp.d.ts" />
+/// <reference path="../es6-promise/es6-promise.d.ts" />
 
 declare module "gulp-help-doc" {
 
     import gulp = require('gulp');
-    import promise = require('es6-promise');
+    import Promise = require('es6-promise');
 
     namespace usage {