memops are nodes that have memory inputs, you can generically query them
for their memory input. We can also get rid of get_fragile_op_mem in
favor of get_memop_mem.

(releases don't have firm_revision.h so we need to check for
HAVE_FIRM_REVISION_H define)

Moves code from ifg dot-file dumpers around and produces .vcg graphs
now (ycomp layout is way better than xdot)

(no changes in functionality)

Fix the size reduction stuff which happily assigned non-allocatable
registers. It worked by chance on x86 as all non-allocatable registers
come last.

(There is a timelimit option in becopyilp anyway)

(They are passed in integer registers, so we can immediately create
integer constants)

We just define that the only reason a Load/Store node can use the
exception edge is a NULL pointer. Misaligned Load/Store is a problem for
low-level languages which don't use exception edges anyway.

We simply always assume that Sel can only return a null pointer if
its input is a null pointer.

this is part of the initiative to move object-orientation support stuff
out of libfirm into liboo

build_edges_walker calls get_block_n on block preds, possibly consing
and hashing a node which init_lh_walker couldn't reach via
irg_walk_anchors.

This fixes a crash I see when compiling Postgres.

This should fix all known bugs, make the code easier to read and more
robust.