target node id's added to module

I added the node id's of the discovered links to the block. The id's are use as keys of the array of links. This is useful if you want to fetch more fields from the nodes in the related links block using node_load();

the $links array was in this form:

[0] => '<a href="alias for node/2321">linktext</a>',
[1] => '<a href="alias for node/114">linktext</a>',
[2] => '<a href="alias for node/1256">linktext</a>'

and is now

[2321] => '<a href="alias for node/2321">linktext</a>',
[114] => '<a href="alias for node/114">linktext</a>',
[1256] => '<a href="alias for node/1256">linktext</a>'