ldstop: further cleanup
ia32: fix use_frame setting in set_address()

The bug didn't affect any existing code, but the fix is necessary for code I am
working on.
ia32_transform: mark several utility load/stores as floating

If a load/store has a compiler generated entity as address, then we can
be sure that they won't produce null-pointer exceptions so we can move
them around.
improve comment
cleanup

Adapt indentation/brace style to rest of libfirm.
lower_dw: remove unnecessary re-enqueue case in lower_Store
fixed wrong error message in verifier
lower_dw: cleanup
introduce Bitcast node
handle Bitcast node in lower_dw and lower_softfloat
ia32: support Bitcast node
tv: cleanup {fc,sc}_val_from_bytes() and introduce {fc,sc}_val_to_bytes()
add tarval_bitcast()
iropt: add localopt rules for Bitcast
iropt: use Bitcast to optimizee load-after-load and loaf-after-store
ldstopt: use Bitcast node for load-after-load and load-after-store
lower_calls: add possibility to return small arrays as int values

This is necessary for ia32 calling conventions for complex float numbers.
preserve debug info
Constbits: Preserve leading zeros for Shr and Shrs.
Optimization only works for two's complement modes.