Load extension strings using gl::GetStringi rather than gl::GetString
Load extension strings using gl::GetStringi rather than gl::GetString

gl::GetString(gl::EXTENSIONS) is not supported in forward compatible contexts, and returns a null pointer (segfault ahoy!)

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