Avoid calling g_base_info_get_name on GI_INFO_TYPE_TYPE

Calling g_base_info_get_name on infos tagged with GI_INFO_TYPE_TYPE will
cause a crash. Avoid this by adding _safe_base_info_get_name and using that
throughout the bindings.
Logged GI bug as: https://bugzilla.gnome.org/show_bug.cgi?id=709456

https://bugzilla.gnome.org/show_bug.cgi?id=709008