Specifically, in all Underscore "collection" functions which treat their
arguments polymorphically as either "object-like" or "array-like", don't
treat arguments with `x.constructor === Object` as arrays (except for
the 'arguments' object).
Fixes#594. Fixes#1737.
Until we figure out some solution to this (or switch to lo-dash), I'm going to
remove 1.4.4 so I can get work done on top of devel.
Revert "upgrade package underscore too"
This reverts commit 7022916fb4.
