[gitignore] ignore TAGS and new test
[gitignore] ignore TAGS and new test

* ignore files generated by make tags
* ignore the newly introduced premult test

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