install mocha npm module
install expect npm module
instal superagent npm module
add simple test for random image response
installed gulp-mocha module
small update to gulpfile
added test task to gulpfile
Merge branch 'add_simple_test'

* add_simple_test:
  added test task to gulpfile
  small update to gulpfile
  installed gulp-mocha module
  add simple test for random image response
  instal superagent npm module
  install expect npm module
  install mocha npm module