Add precision to DateTime.Humanize about humanizer

[wahidshalaly]

I think it can be better if we defined precision as percentage. Let's say by default precision = 0.75 if someone prefers to override it to be either 0.5 or 0.95 for example, that's fine.

0.75 of a minute => if (delta >= 45 seconds) => about a minute
0.75 of a day => if (delta >= 18 hours) => about a day
0.75 of month (30 days) => if (delta >= 22.5 days) => about a month
0.75 of year (365 days) => if (delta >= 273.75 days) => about a year

There's another place we can examine for ideas.. Ruby::ActionView::Helpers::DateHelper distance_of_time_in_words

[MehdiK]

That's a great idea @waheedsayed. Thanks.

By breaking change I didn't mean API breaking change but behavioural. After this change the call that would previously return "a few hours ago" will return "yesterday" and that's a breaking change from my point of view.

I think we could implement this and set the default to 1 for now, and as part of V2 we could decrease it a bit.

[MehdiK]

After reading through #114 by @waheedsayed, it turns out the current implementation is precision based but the (.75) precision is precalculated and hardcoded on each time unit! So we can replace the existing algorithm with the one created in #114.

[MehdiK]

Done in #165