style fixes for comments * find-dialog.cc, find-dialog.h, display.cc, error.cc, gl-render.cc, graphics.cc, graphics.in.h, max.cc, oct-handle.h, oct-obj.h, oct-stream.cc, oct.h, pr-output.cc, profiler.cc, str2double.cc, symtab.cc, toplev.cc, toplev.h, xgl2ps.c, zfstream.cc, zfstream.h, __glpk__.cc, audiodevinfo.cc, colamd.cc, symbfact.cc, ov-classdef.cc, ov-classdef.h, ov-java.cc, op-int.h, pt-pr-code.cc, pt-walk.h: Use C++-style comments where possible.

--- a/libinterp/corefcn/toplev.cc	Fri Dec 18 22:06:22 2015 -0500
+++ b/libinterp/corefcn/toplev.cc	Fri Dec 18 22:39:36 2015 -0500
@@ -1554,7 +1554,7 @@
 {
   void *p;
 
-  /* malloc (0) is unpredictable; avoid it.  */
+  // malloc (0) is unpredictable; avoid it.
   if (sz == 0)
     sz = 1;
   p = gnulib::malloc (sz);