If we weren't started with special privileges, try to figure out if

If we weren't started with special privileges, try to figure out if
we're running from inside an OS X app bundle and, if we are, save the
pathname of the top-level bundle directory and use it to get the
pathnames of global data files, plugins, and Python modules.

This obviates the need to set special environment variables for them in
the launcher scripts, so get rid of the commands to do that.

The @rpathification of binaries also obviates the need for the
commented-out setting of DYLD_LIBRARY_PATH, so get rid of that as well.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@51306 f5534014-38df-0310-8fa8-9805f1628bb7