futures that clear conveyed bindings after execution.

Fixes memory leak described in https://clojure.atlassian.net/browse/CLJ-2619

An implementation of clojure.core/every-pred with a simple operational equivalence.

Variant of `clojure.core/areduce` that supports naming the array.

An alternative to `clojure.core/run!` that does not short-circuit on reduced.

An implementation of clojure.core/some-fn with a simple operational equivalence.

Drop-in replacements for `clojure.test/{deftest,testing}` that (when used
together) enhances uncaught exception error messages with the (most likely)
testing context it was thrown from.

Example:

  (deftest my-test
    (testing "foo"
      (doseq [v [1 2 3]]
        (testing v
          (assert (= 1 v))))))

With clojure.test/{deftest,testing} 1.10.3 (notice `foo 2` is not mentioned):

  user=> (test-var #'my-test)
  ;ERROR in (my-test)
  ;Uncaught exception, not in assertion.
  ;expected: nil
  ;actual: java.lang.AssertionError: Assert failed: false
  ;...
    
With {deftest,testing} in this namespace (notice `foo 2` is mentioned):

  user=> (test-var #'my-test)
  ;ERROR in (my-test)
  ;Uncaught exception, possibly thrown in testing context: foo 2
  ;expected: nil
  ;actual: java.lang.AssertionError: Assert failed: false
  ;...