- fix some ref counting problems

- remove an intermittently failing registry test

IShellExecuteHookW_Execute, this should pass through at least
sei_tmp.nShow retrieved from an .lnk file (fStartup).

  _dbg_ILSimpleGetText, make _dbg_ILSimpleGetText return no value since
  nobody is using it.
- Stop dereferencing a possible NULL in pdump since
  _dbg_ILGetDataPointer can potentially return NULL (for instance for
  root or desktop pidl).
- Make shdebugstr_guid use standard wine_dbg_sprintf instead of the
  handmade solution.

GetCharWidth, GetCharABCWidths and GetTextExtentPoint should return
the widths of a linked font's glyphs.

device.

- make a fixme a little less alarmist