…tdouble.js into uhoh-itsmaciek-deep-matchers

Finally looked at implementation and saw that it'd recurse 
infinitely for objects with circular structures, which is 
definitely not good (and will break td.js even when not
using matchers

Trying to implement a recursive element comparator entirely
inside this function would have been really confusing/error
prone (esp. considering how much work has gone into making
lodash's do the right thing). This commit uses the
`_.isEqualWith` function's `customizer` predicate to be able to
selectively compare values that match a condition (or return
undefined to fall back to default behavior.

In our case, if the expected element is a matcher (which we can
determine based on the presence of `__matches`), then we will
try to match it to the actual element. 

This fixes e4ea059

There's no apparent test for this.

(But alas, tethering on 2G data does not agree with `npm`)