Added standard texture constructors
Added standard texture constructors

alexcrichton/gfx,JohnColanduoni/gfx,mitchmindtree/gfx-rs,red75prime/gfx,ColinKinloch/gfx,bvssvni/gfx-rs,gfx-rs/gfx-rs,tanderegg/gfx,davll/gfx,Bastacyclop/gfx,ColinKinloch/gfx,sectopod/gfx-rs,JohnColanduoni/gfx,tempbottle/gfx,aepsil0n/gfx-rs,tanderegg/gfx