Adapted to the new dependency edges

revert commit that placed consts in startblock, the old code did an equally good job (though a bit slower) and avoided placing consts into the prologe

  of a mort smart placement
- (Also forgot to mention in my last committ that I fixed a bug that sometimes
  produced double spills in the morgan spiller)

- Make ia32_Push and ia32_Pop return their stackpointer adjustment
- replaced stack_dir enum + unsigned offsets with normal integer offsets
- make schedule verifier detect dead nodes in schedule

create all convs, remember those to be killed and kill them after transformation (to preserve modes during transformation)

  - separated constant placement and reference mode changes
  - place constants now in "optimal" block (smallest user dominator)
removed some unused variables

fixed am candidate checker (handle special case loops where the load could be dependent through memory phi on irn)

moved some functions to util module

moved irg finish functions into this module
fixed indenting

Fixed output for be_Return

enabled Push peephole optimization