Implement multi-module feature and bulk-memory feature (#271)

Refine wasm loader and aot loader
Fix potential issue of os_mmap/os_munmap
Update document

core/iwasm/compilation/aot.c

@@ -60,6 +60,10 @@ aot_create_mem_init_data_list(const WASMModule *module)
       goto fail;
     }
 
+#if WASM_ENABLE_BULK_MEMORY != 0
+    data_list[i]->is_passive = module->data_segments[i]->is_passive;
+    data_list[i]->memory_index = module->data_segments[i]->memory_index;
+#endif
     data_list[i]->offset = module->data_segments[i]->base_offset;
     data_list[i]->byte_count = module->data_segments[i]->data_length;
     memcpy(data_list[i]->bytes, module->data_segments[i]->data,