Precise diffs

So there are some things to discuss here. EG:
"2014-04-26 13:00:00", "2013-04-26 13:00:00" will produce "1 year, 1 week, 2 days ago" instead of one year. Dunno atm if this is related to computations or php internals. Will check more when i'll have time. Meanwhile you can take a look and perhaps you'll know