dd ui_widget_set_tooltip_text() as a convenience function to easily set tooltips for widgets. It uses gtk_widget_set_tooltip_text() on GTK >= 2.12 otherwise the old tooltips API.Use ui_widget_set_tooltip_text().
Use ui_widget_set_tooltip_text() in the plugins.

git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@3250 ea778897-0a13-0410-b9d1-a72fbfd435f5