Exclude clojure.core/abs, fixes #82

Author: imrekoszo

src/java_time.clj

@@ -1,5 +1,5 @@
 (ns java-time
-  (:refer-clojure :exclude (zero? range iterate max min contains? format))
+  (:refer-clojure :exclude (zero? range iterate max min contains? format abs))
   (:require [java-time.potemkin.namespaces :as potemkin]
             [java-time.util :as jt.u]
             [java-time core properties temporal amount zone single-field local chrono

src/java_time/core.clj

@@ -1,5 +1,5 @@
 (ns java-time.core
-  (:refer-clojure :exclude (zero? range max min))
+  (:refer-clojure :exclude (zero? range max min abs))
   (:import [java.time.temporal ValueRange]
            [java.time.chrono Chronology]))