Fixed bug by re-indexing positions after node delete.

unlinkNodeById now reindexes the positions of the remaining nodes in
the tree.
Added duplicate node functionality

Duplicates a node and inserts it next in the tree, does not copy child
nodes.
Defaults to opening duplicated node in rename mode

auto increments numerical postfix
comment typo
Hack fix for null instance bug after delete

TODO - fix cause of bug!
select node after duplicate
return status and id on duplcate and copy
Fixed invalid cache after copy bug

TODO naming of getSubdocByNodeId() in delta updates class?
Defaults to opening copied node in rename mode
Fixed text naming issue

In some instances the anchor title did not exist.