Generate n renderbuffer object names

Property definitions

glesv2 :: glesv2 $ Sys :: glGenRenderbuffers
# Generate `n` renderbuffer object names
fun glGenRenderbuffers(n: Int): Array[Int]
do
	var array = new CIntArray(n)
	native_glGenRenderbuffers(n, array.native_array)
	var a = array.to_a
	array.destroy
	return a
end
lib/glesv2/glesv2.nit:721,1--729,3