Add simple script to export release tarball right from Git

The files not to be present in the release tarballs are filetered based
on the contents of the .gitattributes files

Change-Id: If12eb00cf174f5d5b6dfffd56685b078a4593bf8
Reviewed-on: https://code.wireshark.org/review/2402
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Gerald Combs <gerald@wireshark.org>

.gitattributes

@@ -1 +1,6 @@
-* text=auto
+*              text=auto
+/test          export-ignore
+.bzrignore     export-ignore
+.gitattributes export-ignore
+.gitignore     export-ignore
+.gitreview     export-ignore

tools/.gitattributes

@@ -0,0 +1,2 @@
+dftestfiles export-ignore
+dftestlib   export-ignore

tools/git-export-release.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+#
+# creates a release tarball directly from git
+#
+# Copyright 2011 Balint Reczey <balint@balintreczey.hu>
+#
+# Wireshark - Network traffic analyzer
+# By Gerald Combs <gerald@wireshark.org>
+# Copyright 1998 Gerald Combs
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# first paremeter if set is a git commit, like v1.12.0-rc1 or 54819e5699f
+# by default HEAD is used
+COMMIT="HEAD"
+if test -n "$1"; then
+  COMMIT="$1"
+fi
+VERSION=$(git describe --tags ${COMMIT} | sed 's/^v//')
+
+git archive --prefix=wireshark-${VERSION}/ ${COMMIT}  | bzip2 > wireshark-${VERSION}.tar.bz2