API Cleanup

sec/second in-secs/in-seconds in-msecs / in-millis

Added to-epoch (unix seconds, which is standard in a lot of places) and did a little bit of stylistic cleanup.

(sec ...) protocol implementations have a deprecation message attached. if you prefer to log the deprecation by some means other than that a println, load the lib and logic you want, it's just a defn.

It should be noted that we were already using `refer-clojure :exclude` for extend.

Not sure why the PR picked up those older commits that had already been merged.