sequence.go
func FindSequenceOnDisk(pattern string, opts ...FileOption) (*FileSequence, error) {
	return FindSequenceOnDiskPad(pattern, PadStyleDefault, opts...)
}
func FindSequenceOnDisk(pattern string, opts ...FileOption) (*FileSequence, error) {
	return FindSequenceOnDiskPad(pattern, PadStyleDefault, opts...)
}
// FindSequenceOnDisk takes a string that is a compatible/parsible
// FileSequence pattern, and finds a sequence on disk which matches
// the Basename and Extension.
//
// By default the patterns frame value and padding characters are ignored and
// replaced by a wildcard '*' glob. If you want to match on a specific frame
// padding length, pass the option StrictPadding
//
// If no match is found, a nil FileSequence is returned.
// If an error occurs while reading the filesystem, a non-nil error
// is returned.
//
// Example:
//    // Find matches with any frame value
//    FindSequenceOnDisk("/path/to/seq.#.ext")
//
//    // Find matches specifically having 4-padded frames
//    FindSequenceOnDisk("/path/to/seq.#.ext", StrictPadding)