added be_ifg_check_performance() to check speed and memory needed for the creation and the usage of the four ifg variants std, list, clique and pointer

- place copies in a separate walk before the belady algorithm so that they get correctly taken into account when spilling

removed const from struct member

- There is a difference between spilling a whole phi or only spilling the result of a phi. Change belady spiller to respect this (again)

- Fixed bug in spilling: phi nodes that depend on itself should generate loops in the mem-phi as well

- beladie spiller completely ignores ignore register now

doxygen docu added

- Morgan now calls be_spill_phi when spilling phi nodes
- no need to use beinsn in morgan analysis phase, simple iterating over in_edges is enough
- fixed bug in morgan spiller that marked some values as livethrough unused which were not

so we push all blocks on a waitq first :-(

BugFix: x87_create_fpush pushed the wrong register
extended x87_push: allow double push