mpay_plugin_method_channel library

1. mpay_plugin package
2. documentation
3. mpay_plugin_method_channel.dart

mpay_plugin package

1. Libraries
2. arguments
3. mpay_plugin
4. mpay_plugin_method_channel
5. mpay_plugin_platform_interface
6. response/cancelable
7. response/wechat_response
8. result_model