updated deprecated dependencies (#1953)

* replaced deprecated gulp-minify-css with gulp-clean-css
* updated mocha

gulpfile.js

@@ -3,7 +3,7 @@ var async = require('async');
 var gulp = require('gulp');
 var gutil = require('gulp-util');
 var concat = require('gulp-concat');
-var minifyCSS = require('gulp-minify-css');
+var cleanCSS = require('gulp-clean-css');
 var rename = require("gulp-rename");
 var webpack = require('webpack');
 var uglify = require('uglify-js');
@@ -176,7 +176,7 @@ gulp.task('bundle-css', function () {
       .pipe(gulp.dest(DIST))
 
     // TODO: nicer to put minifying css in a separate task?
-      .pipe(minifyCSS())
+      .pipe(cleanCSS())
       .pipe(rename(VIS_MIN_CSS))
       .pipe(gulp.dest(DIST));
 });

package.json

@@ -38,14 +38,14 @@
     "clean-css": "^3.4.10",
     "emitter-component": "^1.1.1",
     "gulp": "^3.9.1",
+    "gulp-clean-css": "^2.0.11",
     "gulp-concat": "^2.6.0",
-    "gulp-minify-css": "^1.2.4",
     "gulp-rename": "^1.2.2",
     "gulp-util": "^3.0.7",
     "hammerjs": "^2.0.6",
     "keycharm": "^0.2.0",
     "merge-stream": "^1.0.0",
-    "mocha": "^2.4.5",
+    "mocha": "^2.5.3",
     "moment": "^2.12.0",
     "propagating-hammerjs": "^1.4.6",
     "rimraf": "^2.5.2",