Fragment caching removed and project#show JS fixed

Kochiku's tendency to modify things multiple times in the same second is causing the fragment caches to show stale data, so we're going to disable fragment caching. Action caching can experience the same issue, but with much lower likelihood, so we'll be keeping our eye on that.
The javascript change fixes a bug that caused NaN:aN to be shown as the elapsed time on the project#show page, which was introduced alongside the caching.
need a better variable name here. probably `dom_id_for_part`