bump clojure version to 1.9.0-alpha14 due to spec usage

Author: puredanger

pom.xml

@@ -90,7 +90,7 @@
 
   <properties>
     <!-- 1.8.0 is required to run cljs test suite -->
-    <clojure.version>1.8.0</clojure.version>
+    <clojure.version>1.9.0-alpha14</clojure.version>
   </properties>
 
   <pluginRepositories>