Rename "range.c" and "range.h" to "packet-range.c" and "packet-range.h";

Rename "range.c" and "range.h" to "packet-range.c" and "packet-range.h";
they should ultimately be split into files with routines that handle
ranges, which are just subsets of [0,2^32), and packet ranges, which are
subsets of the packet list, possibly specified by a range.

Move them into epan, so they can be used by, for example, utilities that
handle ranges, such editcap.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@11890 f5534014-38df-0310-8fa8-9805f1628bb7