Template based resource icons

Add „template_[[add templete id here]]“ to each node in the resource
tree. Allows to customize icons in the tree according to the template
used for this item. See it in action:
https://dl.dropboxusercontent.com/u/1840535/Download.png
Corrected typo...
Changes to template management to allow custon icons in the resource tree

Enhanced version of last commit
Additional changes necessary v2.3
Changed charset encoding to utf-8

Added some changes for MODX 2.3
Update getnodes.class.php
Enable Template-based icons in Resource tree

Merge remote-tracking branch 'origin/pr/757' into develop

* origin/pr/757:
  Update getnodes.class.php
  Changed charset encoding to utf-8
  Additional changes necessary v2.3
  Changes to template management to allow custon icons in the resource tree
  Corrected typo...
  Template based resource icons