Releases for Corresponding node references

- Features integration
- Numerous bug fixes

Drupal 7 port of the 6.x-4.1 branch.

• cck check the allowed node references + overloading warning #461602: nodereferences with single instances

The delta count issue #730986: Refactor to use content module's data APIs (and duplicates #672732: Wrong 'delta' count

db specific sql removed
multiple add more autocomplete prevention
call by reference removed from settings file

Support for content types with references to multiple node types

Call by reference bug fixed

The module is now able to do single nodereferences.
A bug is fixed when using the module with multiple instance on the same node type.
The module gained performance by reducing the amount of queries executed.

The nid of a deleted node still existed in the tables. CCK deleted the nodes in the nid field but apparently not in field_'ref_name_field'_nid.

The module as of version 6.x-1.8 now deletes these rows too. So no other node references content field table has rows where the reference field points to a non existing node.

fixes a php warning and delete the NULL field

Fixed missing brackets in querries.