Add definitions for gulp-htmlmin (https://github.com/jonschlinkert/gulp-htmlmin)

gulp-htmlmin/gulp-htmlmin-tests.ts

@@ -0,0 +1,11 @@
+/// <reference path="gulp-htmlmin.d.ts" />
+/// <reference path="../gulp/gulp.d.ts" />
+
+import * as gulp from 'gulp';
+import * as htmlmin from 'gulp-htmlmin';
+
+gulp.task('minify', function() {
+  return gulp.src('src/*.html')
+    .pipe(htmlmin({collapseWhitespace: true}))
+    .pipe(gulp.dest('dist'))
+});

gulp-htmlmin/gulp-htmlmin.d.ts

@@ -0,0 +1,18 @@
+// Type definitions for gulp-htmlmin v1.3.0
+// Project: https://github.com/jonschlinkert/gulp-htmlmin
+// Definitions by: Tanguy Krotoff <https://github.com/tkrotoff>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../node/node.d.ts" />
+/// <reference path="../html-minifier/html-minifier.d.ts" />
+
+declare module 'gulp-htmlmin' {
+    import * as HTMLMinifier from 'html-minifier';
+
+    namespace htmlmin {
+    }
+
+    function htmlmin(options?: HTMLMinifier.Options): NodeJS.ReadWriteStream;
+
+    export = htmlmin;
+}