#8 Improve "const correctness"

[Markus Elfring]

Would you like to apply the advices from the article
"http://en.wikipedia.org/wiki/Const_correctness" to
your sources?
I suggest to add the key word "const" to the type
specifiers for parameters like the following.
- outname (functions ".+_writepkt")

http://cvs.sourceforge.net/viewcvs.py/ipaudit/ipaudit-1/src/ipdbase.h?rev=1.3&view=markup

- h, k (functions "ht_find.+", "ht_gethash")
h (functions "ht_getoldest", "ht_debuginfo")

http://cvs.sourceforge.net/viewcvs.py/ipaudit/ipaudit-1/src/hash.h?rev=1.2&view=markup