Release 0.6.1

• Fix an issue of gtk-widget-get-name
• Add <gtk-tool-button>
• Release tarball name is now Gauche-gtk2-x.x.tgz instead of Gauche-gtk-x.x.tgz, reflecting the package name.

Release 0.6

It's been too long since the last release; there have been sporadic bug fixes over years. No new features, but it's stable.