grn_ts: support operators "/" and "%" for score adjustment
grn_ts: support operators "/" and "%" for score adjustment

GitHub: #387

naoa/groonga,cosmo0920/groonga,groonga/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,kenhys/groonga,hiroyuki-sato/groonga,hiroyuki-sato/groonga,hiroyuki-sato/groonga,hiroyuki-sato/groonga,cosmo0920/groonga,kenhys/groonga,hiroyuki-sato/groonga,cosmo0920/groonga,groonga/groonga,groonga/groonga,hiroyuki-sato/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,kenhys/groonga,cosmo0920/groonga,groonga/groonga,kenhys/groonga,kenhys/groonga,naoa/groonga,cosmo0920/groonga,kenhys/groonga,naoa/groonga,naoa/groonga,groonga/groonga,naoa/groonga,cosmo0920/groonga,naoa/groonga,naoa/groonga,hiroyuki-sato/groonga,komainu8/groonga,komainu8/groonga,naoa/groonga,groonga/groonga,cosmo0920/groonga,groonga/groonga,komainu8/groonga,komainu8/groonga,cosmo0920/groonga,groonga/groonga,hiroyuki-sato/groonga