package import path should not use relative paths

[parkghost]

nnseg.go use a relative path for import gonn package, the method have a problem that make application developer can't use remote package directly.

e.g.

import (
    "fmt"
    "github.com/fxsjy/goseg/goseg"
)

var text = `透過攝取天然的食物、規律運動等，強化人體的免疫系統，自然能排出體內有害人體的代謝物質，不僅促進身體健康，整個人也會顯得精神奕奕。`

func main() {
    for _, word := range goseg.Cut([]rune(text)) {
        fmt.Println(word)
    }
}

$ go build
test.go:5:2: local import "./gonn" in non-local package

the import path "./gonn" should replace by "github.com/fxsjy/goseg/goseg/gonn" in nnseg.go