Allow use of non-numeric (e.g. UUID) values for ObjectIdentity.getIdentifier()

Prior to this commit, the ObjectIdentity id had to be a number. This
commit allows for domain objects to use UUIDs as their identifier. The
fully qualified class name of the identifier type can be specified
in the acl_object_identity table and a ConversionService can be provided
to BasicLookupStrategy to convert from String to the actual identifier
type.

There are the following other changes:

 - BasicLookupStrategy has a new property, aclClassIdSupported, which
 is used to retrieve the new column from the database. This preserves
 backwards-compatibility, as it is false by default.

 - JdbcMutableAclService has the same property, aclClassIdSupported,
 which is needed to modify the insert statement to write to the
 new column. Defaults to false for backwards-compatibility.

 - Tests have been updated to verify both the existing functionality
 for backwards-compatibility and the new functionality.

Fixes gh-1224

acl/src/test/resources/jdbcMutableAclServiceTestsWithAclClass-context.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+
+  <import resource="jdbcMutableAclServiceTests-context.xml"/>
+
+  <bean id="aclClassIdUtils" class="org.springframework.security.acls.jdbc.AclClassIdUtils">
+    <property name="conversionService">
+      <bean class="org.springframework.core.convert.support.DefaultConversionService"/>
+    </property>
+  </bean>
+  <!-- Overridden bean definitions -->
+
+  <bean id="aclService" class="org.springframework.security.acls.jdbc.JdbcMutableAclService">
+    <constructor-arg ref="dataSource"/>
+    <constructor-arg ref="lookupStrategy"/>
+    <constructor-arg ref="aclCache"/>
+    <property name="aclClassIdSupported" value="true"/>
+    <property name="aclClassIdUtils" ref="aclClassIdUtils"/>
+  </bean>
+
+  <bean id="lookupStrategy" class="org.springframework.security.acls.jdbc.BasicLookupStrategy">
+    <constructor-arg ref="dataSource"/>
+    <constructor-arg ref="aclCache"/>
+    <constructor-arg ref="aclAuthorizationStrategy"/>
+    <constructor-arg>
+      <bean class="org.springframework.security.acls.domain.ConsoleAuditLogger"/>
+    </constructor-arg>
+    <property name="aclClassIdSupported" value="true"/>
+    <property name="aclClassIdUtils" ref="aclClassIdUtils"/>
+  </bean>
+</beans>