Copy 'n' Paste duplicates record_id causing tag conflicts

[saxondigital]

Currently tags are saved and loaded using record_id to associate them with their nodes. This is a problem with cut n paste and the way the tag table is saved. Implementing np_tag_id can help solve this.

Related issues:

• Add 'tag_id' to node table to allow multiple unique tags per record_id #197
• Copy & Paste links point to original parent B-end (not the copy) #330