Allow NULL for clutter_text_set_text()
Allow NULL for clutter_text_set_text()

As a convenience, if NULL is passed for the text argument of
clutter_text_set_text() (and for consistency,
clutter_text_set_markup()), treat that the same as "".

heysion/clutter-clone,nobled/clutter,rkudiyarov/clutter_osx,spatulasnout/clutter,djdeath/clutter-multithreaded,rkudiyarov/clutter_osx,spatulasnout/clutter,heysion/clutter-clone,djdeath/clutter-android,jigpu/clutter,nobled/clutter,dlespiau/clutter,djdeath/clutter-android,Distrotech/clutter,GNOME/clutter,djdeath/clutter-multithreaded,ebassi/clutter,spatulasnout/clutter,Distrotech/clutter,djdeath/clutter-multithreaded,ebassi/clutter,Distrotech/clutter,heysion/clutter-clone,ebassi/clutter,rkudiyarov/clutter_osx,rkudiyarov/clutter_osx,jigpu/clutter,collects/clutter,heysion/clutter-clone,jigpu/clutter,jigpu/clutter,collects/clutter,dlespiau/clutter,tardyp/clutter,Distrotech/clutter,kerrickstaley/clutter-vala,djdeath/clutter-multithreaded,dlespiau/clutter,ebassi/clutter,collects/clutter,tardyp/clutter,GNOME/clutter,djdeath/clutter,djdeath/clutter,djdeath/clutter-android,djdeath/clutter,djdeath/clutter,nobled/clutter,spatulasnout/clutter,tardyp/clutter,djdeath/clutter,kerrickstaley/clutter-vala,kerrickstaley/clutter-vala,jigpu/clutter,Distrotech/clutter,djdeath/clutter-android,collects/clutter,GNOME/clutter,jigpu/clutter,heysion/clutter-clone,GNOME/clutter,ebassi/clutter,kerrickstaley/clutter-vala,djdeath/clutter-android,collects/clutter,djdeath/clutter,GNOME/clutter,Distrotech/clutter,spatulasnout/clutter