Make every ModuleItem know its ModuleInfo

This was trivial to expose, and necessary to avoid some otherwise
necessary ugliness in the ModuleService#load and #save methods.
See next commit for details.

Author: ctrueden

src/main/java/org/scijava/module/AbstractModuleItem.java

@@ -84,6 +84,11 @@ public String toString() {
 
 	// -- ModuleItem methods --
 
+	@Override
+	public ModuleInfo getInfo() {
+		return info;
+	}
+
 	@Override
 	public Type getGenericType() {
 		return getType();

src/main/java/org/scijava/module/ModuleItem.java

@@ -47,6 +47,9 @@
  */
 public interface ModuleItem<T> extends BasicDetails {
 
+	/** Gets the {@link ModuleInfo} to which this item belongs. */
+	ModuleInfo getInfo();
+
 	/** Gets the type of the item. */
 	Class<T> getType();