#540434 by bitman: Fixed default value for fields.
Minor refactoring, and text changes.

2 cases of updating:
1) The table doesn't exist.
2) The table's ctid field should be change to nctid.
This is a fix for PostgreSQL compatibility.
Also used patched #461406 by AlexisWilke

Fixed a bug with converting books.
Cleaned up code.
Wrote a bit of documentation.

Added hook_node_convert_change, to allow node modules perform needed changes when converting. Fixed a bug on bulk convert when not all nodes are chosen.

Initial commit of Node Convert module. Node Convert adds a menu tab Convert on the node view, which gives you the possibility of converting the node from one node type, to another. Also it gives the ability of transfering the custom cck fields to other destination cck fields or just discard them. Currently the module works only with basic core cck fields, which dont repeat.