Feature/unix time

-Adds a helper to convert from our calendar-str format to a unix time http://en.wikipedia.org/wiki/Unix_time

-Add cljs-time helpers for converting from unix-time to cljs-time DateTime instances, as well as formatting, extracting days/months/years, and helpers to test if a given date is in the future or past, or if a date range is currently in the present (happening?).

-Properly format the namespace
make a protocol, implement it for js/date and for the cljs-time one