Add new module refl-die with general Die-related tools
Add __refl_attr_integrate and __refl_die_name to the refl-die module

- Convert several places to using this instead of coding the same by
  hand.

- Note that refl_method_name doesn't set name to "???" if unavailable.
  This may come back again if deemed useful.
Clean up error handling

- I'm not entirely sure why REFL_E_REFL/REFL_ME_DWARF pair was handled
  specially.  Keep REFL_E_REFL in, but use REFL_E_DWARF for errors
  related to Dwarf.

- Drop __refl_error, which was a wrapper around __refl_seterr_2 with
  REFL_E_REFL as first argument.  It was confusing.
Move attribute-matching functions to refl-die
Die tree iteration primitives are __refl_die_tree and __refl_die_children
Fixlets
Add __refl_die_type
Add refl_object_type
Some assemblies may be objects

- Namely global variables.
Add refl_type_dump, mainly for debugging purposes
Update the test case