Nested structs should not require the use of the none format.

[ianlopshire]

Currently, to decode nested structs properly, you must use the none format option.

type Nested struct {
	First  string `fixed:"1,3"`
	Second string `fixed:"4,6"`
}

type Test struct {
	First  string `fixed:"1,3"`
	Second Nested `fixed:"4,9,none"`
}

This is a breaking change and should be released as part of a major version bump.