- some code cleanup
- avoids the case where 2 dumpers are registered

This also corrects dumping schedule edges.

Projs are not scheduled, so they will fail this test later on.

Remove now redundant (and sometimes wrong) location info from the panic messages.

It should only be used by construction algorithms

This tries to get the names in a consistent format. We basically have 2
views on register allocation/constraints now:

1) Register Requirements and Assigments are per-instruction. Each
   instruction has requirements on its inputs and outputs, register get
   assigned for outputs of an instruction (assignment is an attribute of
   an instruction, not of the Proj-nodes).
   The internal datastructures model this form!

   The functions here have the form:
     arch_get_irn_register_req_in(node, input_nr)
     arch_get_irn_register_in(node, input_nr)
     arch_get_irn_register_req_out(node, output_nr)
     arch_set_irn_register_out(node, output_nr, register)

2) Register Requirements and Assignments are on firm-values. This view
   allows to query/assign requirements and registers at the Proj nodes
   instead of the repsective predecessors.
   This is a convenience interface modeled on top of the other!

   The functions have the form:
     arch_get_irn_register_req(node)
     arch_get_irn_register(node)
     arch_set_irn_register(node, register)

[r28458]

[r28337]

[r28330]

[r28037]

[r27995]

[r27992]

[r27693]

[r27653]

- remove a bunch of code which unexpectedly dependent on current_ir_graph being
  set to something
- fix unnecessary double creation of backedge arrays in some cases

[r27265]

- Introduced be_Start which is now used instead of iro_Start+be_RegParams
- further cleanups and fixes along the way

[r26549]

	* benodes store the out register requirements in backend_info now
	  (this is work towards killing the register_requirement callbacks)
	* ir_graph has a pointer to beirg now
	* Other cleanups

[r26540]

[r26535]

[r26468]

Do not allocate backend info for Projs. Their tuple hold all info and asking the Projs is plain wrong.

[r26337]

- make phi nodes use backend_info instead of phi_handler hashmaps

[r26332]

[r26317]

[r25982]

[r23154]

[r23143]