fixing Export-Package manifest header

Author: erosb

core/pom.xml

@@ -68,9 +68,10 @@
                         <Import-Package>*
                         </Import-Package>
                         <Export-Package>
-                            ${project.artifactId};version=${project.version},
-                            ${project.artifactId}.loader;version=${project.version},
-                            ${project.artifactId}.regexp;version=${project.version}
+                            org.everit.json.schema;version=${project.version},
+                            org.everit.json.schema.loader;version=${project.version},
+                            org.everit.json.schema.regexp;version=${project.version}
+                            org.everit.json.schema.event;version=${project.version}
                         </Export-Package>
                     </instructions>
                 </configuration>