MATH-1670: Remove stat.inference package

Functionality has been transferred to the Commons Statistics inference
module.

Author: aherbert

commons-math-legacy/pom.xml

@@ -133,6 +133,12 @@
       <scope>test</scope>
     </dependency>
 
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-statistics-inference</artifactId>
+      <scope>test</scope>
+    </dependency>
+
   </dependencies>
 
   <build>