Added operator < to BufferSize, removed equivalent functor predicate.
Added operator < to BufferSize, removed equivalent functor predicate.


Former-commit-id: 631f22423a67405e5acbb2ee7e8adbafa2710bc6
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide