Also move ir_nodemap struct into a new irnodemap_t.h file.

This resolves problems with hidden dependencies during code selection, which cause dependency cycles and therefore fixes backend/scheduled.c.
Also it grants the code selection slightly more freedom by not arbitrarily restricting the order by stack dependencies.

Do not use the entity address as number because that makes things
nondeterministic.

Patch submitted by Rich Felker <dalias@aerifal.cx>

Do not use the type address as number because that makes things
nondeterministic.

The official website is http://libfirm.org; the bugtracker is not linked
to the /firm subdir yet but still only available as ~firm/bugs.

be: Pass the input requirements directly to the constructors of nodes, which have a variable number of arguments.