Updated to use Craft's native helpers JsonHelper and IOHelper libraries

Signed-off-by: John Morton <john@johnfmorton.com>
Merge branch 'master' of https://github.com/johnfmorton/Pic-Puller-for-Instagram---Craft

* 'master' of
https://github.com/johnfmorton/Pic-Puller-for-Instagram---Craft:
  Updated to use Craft's native helpers JsonHelper and IOHelper
libraries

Conflicts:
	craft/plugins/picpuller/services/PicPuller_FeedReaderService.php