add example of PSOA dependent slots in exa/datalogPSOA

The schemas associated with this example do not yet exist.
Partial implementation of RuleML/issues-ruleml#78

exa/DatalogPSOA/datalogPSOA.ruleml

@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<?xml-model href="http://deliberation.ruleml.org/1.03/relaxng/datalogPSOA_relaxed.rnc"?>
+<!--<?xml-model href="http://deliberation.ruleml.org/1.03/xsd/datalogPSOA.xsd" type="application/xml" schematypens="http://www.w3.org/2001/XMLSchema"?>-->
+<RuleML xmlns="http://ruleml.org/spec"
+  xmlns:this="http://example.org/datalogPSOA.ruleml"
+  xmlns:xs="http://www.w3.org/2001/XMLSchema"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://ruleml.org/spec http://deliberation.ruleml.org/1.03/xsd/datalogPSOA.xsd">
+
+  <!-- note the addition of the XML Schema namespace because a built-in datatype is used -->
+
+  <!-- a syntactic example rulebase for testing the Datalog PSOA RuleML sublanguage -->
+
+  <Assert mapClosure="universal">
+
+    <Implies node ="this:#rule1">
+      <if>
+        <Atom>
+          <oid><Ind>John</Ind></oid><op><Rel>TA</Rel></op>
+          <slotdep><Ind>workload</Ind><Ind>high</Ind></slotdep>
+        </Atom>
+      </if>
+      <then>
+        <Atom>
+          <meta>
+            <Atom><Rel>P</Rel></Atom>
+          </meta>
+          <op>
+            <Rel>friend</Rel>
+          </op>
+          <slot>
+            <Ind>time</Ind>
+            <Data xsi:type="xs:dateTime">2001-10-26T21:32:52+02:00</Data>
+          </slot>
+          <Var>x</Var>
+          <Var>y</Var>
+          <Ind>Steph</Ind>
+          <Reify>
+            <Reify>
+              <Implies>
+                <And>
+                  <Atom>
+                    <Rel>buy</Rel>
+                    <Var>person</Var>
+                    <Var>merchant</Var>
+                    <Var>object</Var>
+                  </Atom>
+                  <Atom>
+                    <Rel>keep</Rel>
+                    <Var>person</Var>
+                    <Var>object</Var>
+                  </Atom>
+                </And>
+                <Atom>
+                  <Rel>own</Rel>
+                  <Var>person</Var>
+                  <Var>object</Var>
+                </Atom>
+              </Implies>
+            </Reify>
+          </Reify>
+        <slot>
+            <Ind>location</Ind>
+            <Data xsi:type="xs:positiveInteger">2</Data>
+          </slot>
+        </Atom>
+      </then>
+    </Implies>
+
+
+
+  </Assert>
+
+</RuleML>