Add session.Options values to cookie

[ebiiim]

Just like the original implementations below, options (MaxAge, Path, etc...) should be set to the cookie.

https://github.com/gorilla/sessions/blob/9cb0b0a3e38d07f41143f03013eaf0a3243fb474/store.go#L102
https://github.com/gorilla/sessions/blob/9cb0b0a3e38d07f41143f03013eaf0a3243fb474/store.go#L210

This pull request solves #1.

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[ebiiim]

@googlebot I signed it!

[leobrines]

Hi! Will any revision be done?