Removed obsolete gulp-nodemon (#435)

Closes #420

* Remove gulp-nodemon from dev dependencies
* Remove required dependency from gulpfile

gulpfile.js

@@ -3,7 +3,6 @@ var gulp = require('gulp');
 // gulp plugins and utils
 var gutil = require('gulp-util');
 var livereload = require('gulp-livereload');
-var nodemon = require('gulp-nodemon');
 var postcss = require('gulp-postcss');
 var sourcemaps = require('gulp-sourcemaps');
 var zip = require('gulp-zip');

package.json

@@ -38,7 +38,6 @@
         "cssnano": "3.7.1",
         "gulp": "3.9.1",
         "gulp-livereload": "3.8.1",
-        "gulp-nodemon": "2.1.0",
         "gulp-postcss": "6.1.1",
         "gulp-sourcemaps": "1.6.0",
         "gulp-util": "3.0.7",