Added the concept of DOTIW calculator which will make the Date.Humanize() method very compact & also give us chance to introduce a new way of calculation, precision-based calculation. By this we can have a non-breaking change since that it's optional to choose between the default (old) calculator & the precision-based (new) calculator. Also It'll be open for everyone to have his own calculation if there's a special need.
We didn't fully reset culture settings while disposing.
Implemented precision-based distance of time in words

Duplicated DateHumanizeTests, as PrecisionBasedDistanceOfTimeTests, to examine compatibility with previous calculation method.
Minor refactor: replaced Dotiw by DistanceOfTime in namespaces & types.
Refactored Date.Humanize() unit tests
Added tests for precision-based calculation.
Updated PublicApiApprovalTest