switching in x87
- Only emit externally allocated symbols that are actually used

[r12625]

- more work on state registers for x87 fpu rounding modes

  into other nodes
- correctly fix Copies in x87 simulator

- correctly capture spills and reloads in coalescer code

- use mode_Iu for all nodes producing integer values (because registers are mode_Iu), this gives more possibilities for cse
- use mode_D for all nodes producing float values, this gives more possibilities for cse
- Introduce NoReg and Unknown nodes so we don't have strange projs from the start barrier
- Rewrite transform phase:
  - while transforming we now build a completely new graph on a new irg (while looking at the old graph)
  - no need to transform constants in advance anymore
  - several smaller fixes+cleanups

- New register allocator modules can register themselfes in a list now,
	the same will be done for spillers, copy coalescers, architectures soon

the spillslot coalescer is now a general frame entity coalescer for all nodes that don't have entities yet\n We use that for the lowered float->int and int->float convert nodes now

  where CSE is explicitely forbidden. This fixes some bugs where a cmp
  function was missing.
- Don't make all the nodes mode_T by default. They keep their normal mode
  node and only get set to mode_T is we actually use am_Dest
- get rid of src_mode and tgt_mode node attribute, you can get the modes
  by looking at the conv output mode and the arguments mode. This fixes
  some bugs where the src_mode and tgt_mode attributes were wrong
- cleaned up and fixed some bugs in addressmode optimisation

const are now placed in smallest common dominator block of all it's users
constants have dependency to barrier

- Fix Projs returning wrong register requirements for in positions

- warning fixes

  as the irextbb algo fails for critical edges
- Make sure removed nodes have their preds set to Bad
- some cleanups

  walking occurs before finish phase now
- changed ia32 to do some things transforms from finish phase in after_ra phase
  already but do peephole optimization in finish phase.
- Added a peephole optimisation that transform IncSP,Store cascades to
  Pushs
- Replaced several HASH_PTR with nodeset_hash to make compiler more
  deterministic.

removed code for create_Pop: need to be reimplemented

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)