0.2.0.0 Remove functions which are superseded by upstream

containers has added take, drop, restrictKeys and withoutKeys which are equivalent to take, drop, keepKeys and dropKeys from the map-exts API, respectively. takeLeft/Right and dropLeft/Right have been exposed.

containers:drop/take correspond to dropLeft and takeLeft respectively.

map-exts is now compatible with lts-10.3

0.1.1.0 Add version bound for upstream containers

0.1.0.1 Improve documentation, examples