Add export_tarball tool.
Add export_tarball tool.

It creates a .bz2 tarball with all the sources, but without
.svn directories, and has an option to remove files
which are not required for build, and take a lot of space.

Review URL: http://codereview.chromium.org/155863

git-svn-id: http://src.chromium.org/svn/trunk/src@21384 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: f7bf3b01470973b03925cba01e3865a683be5d6e
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser