Added ptunnel formula.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/ptunnel.rb

@@ -0,0 +1,23 @@
+require 'formula'
+
+class Ptunnel <Formula
+  url 'http://www.cs.uit.no/~daniels/PingTunnel/PingTunnel-0.71.tar.gz'
+  version '0.71'
+  homepage 'http://www.cs.uit.no/~daniels/PingTunnel/'
+  md5 '9b04771d4fa50abc15a6af690b81c71a'
+
+  def install
+    system "make"
+    bin.install "ptunnel"
+    (man+'man8').install "ptunnel.8"
+  end
+
+  def caveats
+    <<-EOS
+    Normally, ptunnel uses raw sockets and must be run as root (using sudo, for example).
+
+    Alternatively, you can try using the -u flag to start ptunnel in 'unprivileged' mode,
+    but this is not recommended. See http://www.cs.uit.no/~daniels/PingTunnel/ for details.
+    EOS
+  end
+end