dbghelp: Base and symbols.

dbghelp: Base and symbols.

- report the correct image base for a symbol which is
  seen as being in a builtin PE module, whilst its debug
  information is gotten from an ELF module
- module_get_debug now returns a pair of modules
  (the requested that has to be presented back to the client
   and the effective one, which contains the debug info)
- reworked SymFromName in order to provide also the revelant
  module base address