v0.7.9: Merge pull request #16 from pepabo/respect_orientation

Respect orientation

v0.7.8: Merge pull request #15 from pepabo/add_error_handling

err == nil && orgRes == nil の場合があったためエラーを追加

v0.7.4: Merge pull request #9 from pepabo/fix_dup_body

allow duplicate read from orgRes.Body

v0.7.3: Merge pull request #8 from pepabo/fallback_webp

webp 変換が失敗したら jpg の最適化処理をする

v0.7.2: Merge pull request #6 from takutakahashi/webp

Convert by only cwebp when .webp ext filepath requested

v0.7.1: Merge pull request #5 from takutakahashi/webp

fix bug for webp: handle 304 as safe

v0.7.0: Merge pull request #4 from takutakahashi/webp

Implemented WebP Convert