Teeny-tiny optimizations:
BenchmarkSprintf-10 37735996 32.31 ns/op 0 B/op 0 allocs/op
BenchmarkItoa-10 591945836 2.031 ns/op 0 B/op 0 allocs/op
BenchmarkFormatUint-10 593701444 2.014 ns/op 0 B/op 0 allocs/op
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>