Adds a *current-options* variable so with-db would honor database specific options

[ls4f]

Finally got to https://github.com/korma/Korma/issues/282 . Not 100% sure that's the best way to go at it. Feedback is welcome :)

[immoh]

Why does it need to be new dynamic var, can't we just call (:options *current-db*)?

Please also get rid of the white space changes.

[ls4f]

Somehow new var seemed cleaner to use, no real reason. Sorry about the auto-indent. Fixed it.

[immoh]

Thanks!