Review swap (GtkSpell C++ bindings)

[Sandro Mani]

Hello,

I'd like to swap reviews for [1] (gtkspellmm30, i.e. the C++ bindings 
for GtkSpell3 - should be fairly quick and easy).

Thanks,
Sandro

[1] https://bugzilla.redhat.com/show_bug.cgi?id=919260