add some initial code so cck field modules can participate in devel_generate. see #187599. patch by moshe weitzman.

you may now generate nodes only of specified types ...  content deletion is slower now but more proper. we only delete nodes from the specified types.

terms on nodes now respect their vocab's multiple property, and requried property ... empty nodequeue if that module is installed and we are killing content.

major update for devel_generate module. lots of stuff like comment threading was busted. further, we were attaching taxonomy terms to nodes in the wrong place (outside of node_save()). all is working ok in my tests except for the main block of links on /admin. for some reason, that isn't showing up.

#150505 Port devel_generate to 6.x. patch by Rok. not perfect, but close enough. see issue for details.

some minor bugs (missing table prefixing, for() off-by-1 error,
missing format_plural(), unnecessary update to {sequences}, etc).