Updated debian/changelog for new upstream release and org.gnome.shell.extensions.TaskBar.gschema.xml installation destination changes

Mentioned changes made in version 26
 - fixes bottom panel issue - panel doesn't cover windows now, see https://github.com/zpydr/gnome-shell-extension-taskbar/issues/8
 * Moved org.gnome.shell.extensions.TaskBar.gschema.xml file to to correct location (/usr/lib/glib-2.0/schemas)