Add gulp file with multiple tasks

- help: receive a list of available tasks
- clean: delete `release` folder
- build-min: minify and copy module to release folder
- copy-module: simple copy of source module to release folder
- build: a combination of `build-min` and `copy-module` tasks

Author: igorissen

Diff for: gulpfile.js

@@ -0,0 +1,60 @@
+var gulp    = require("gulp"),
+    del     = require("del"),
+    plugins = require("gulp-load-plugins")();
+
+var paths = require("./gulp.config.json");
+
+var log    = plugins.util.log,
+    colors = plugins.util.colors;
+
+gulp.task("help", plugins.taskListing);
+
+gulp.task("clean", function (callback) {
+  log("Cleaning: " + colors.blue(paths.release));
+
+  del(paths.release, callback);
+});
+
+gulp.task("build-min", function () {
+  log("Minifying and copying angular module to release folder: " + colors.blue(paths.release));
+
+  return gulp
+    .src(paths.source)
+    .pipe(plugins.ngAnnotate())
+    .pipe(plugins.bytediff.start())
+    .pipe(plugins.uglify())
+    .pipe(plugins.bytediff.stop(bytediffFormatter))
+    .pipe(plugins.rename({ extname: ".min.js" }))
+    .pipe(gulp.dest(paths.release));
+});
+
+gulp.task("copy-module", function () {
+  log("Copying angular module to release folder: " + colors.blue(paths.release));
+
+  return gulp
+    .src(paths.source)
+    .pipe(plugins.ngAnnotate())
+    .pipe(plugins.rename({ extname: ".js" }))
+    .pipe(gulp.dest(paths.release));
+});
+
+gulp.task("build", [ "build-min", "copy-module" ], function () {});
+
+/////////////////////////////////////////////////////////////////////////////////////////////
+
+function bytediffFormatter(data) {
+  var difference = (data.savings > 0) ? " smaller." : " larger.";
+
+  return data.fileName
+    + " went from "
+    + colors.yellow((data.startSize / 1000).toFixed(2) + " kB")
+    + " to "
+    + colors.yellow((data.endSize / 1000).toFixed(2) + " kB")
+    + " and is "
+    + colors.yellow(formatPercent(1 - data.percent, 2) + "%")
+    + difference;
+}
+
+function formatPercent(num, precision) {
+  return (num * 100).toFixed(precision);
+}