redid API yet again - IMenuHandler is now bound to an IBaseMenu instance

implemented MOST natives
removed broadcasting/voting handlers for the time being
fixed a crash bug in basecontext when i didn't obey the api
moved radio displays to a caching stack

--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%40796

core/vm/sp_vm_basecontext.cpp

@@ -194,6 +194,13 @@ int BaseContext::Execute(uint32_t code_addr, cell_t *result)
 		return SP_ERROR_NOT_RUNNABLE;
 	}
 
+	/* tada, prevent a crash */
+	cell_t _ignore_result;
+	if (!result)
+	{
+		result = &_ignore_result;
+	}
+
 	IVirtualMachine *vm = (IVirtualMachine *)ctx->vmbase;
 
 	uint32_t pushcount = ctx->pushcount;