cursor.go
func NewCursor(startinginput string, pointer Pointer, eraseDefault bool) Cursor {
	if pointer == nil {
		pointer = defaultCursor
	}
	cur := Cursor{Cursor: pointer, Position: len(startinginput), input: []rune(startinginput), erase: eraseDefault}
	if eraseDefault {
		cur.Start()
	} else {
		cur.End()
	}
	return cur
}
func NewCursor(startinginput string, pointer Pointer, eraseDefault bool) Cursor {
	if pointer == nil {
		pointer = defaultCursor
	}
	cur := Cursor{Cursor: pointer, Position: len(startinginput), input: []rune(startinginput), erase: eraseDefault}
	if eraseDefault {
		cur.Start()
	} else {
		cur.End()
	}
	return cur
}
// NewCursor create a new cursor, with the DefaultCursor, the specified input,
// and position at the end of the specified starting input.