Issue 60 - correctly delegate to platform for modules with no class loader

It seems Module.getClassLoader will return null for boot layer class loaders
We need to just use the platform loader in this case to do proper delegation

If we don't do this the framework will use the Atomos content that wraps
the module content as the source for creating a bundle class loader.
diff --git a/atomos/src/main/java/org/apache/felix/atomos/impl/modules/ConnectContentModule.java b/atomos/src/main/java/org/apache/felix/atomos/impl/modules/ConnectContentModule.java
index aafaf6c..da389b1 100644
--- a/atomos/src/main/java/org/apache/felix/atomos/impl/modules/ConnectContentModule.java
+++ b/atomos/src/main/java/org/apache/felix/atomos/impl/modules/ConnectContentModule.java
@@ -27,6 +27,7 @@
 
 public class ConnectContentModule implements ConnectContent
 {
+	static final ClassLoader platformLoader = ClassLoader.getPlatformClassLoader();
     final Module module;
     final ModuleReference reference;
     final AtomosLayerModules atomosLayer;
@@ -61,7 +62,7 @@
     @Override
     public Optional<ClassLoader> getClassLoader()
     {
-        return Optional.ofNullable(module.getClassLoader());
+        return Optional.ofNullable(module.getClassLoader()).or(() -> Optional.of(ConnectContentModule.platformLoader));
     }
 
     @Override