Setting view_context instead controller instance

In [setting_render_context](https://github.com/alterego-labs/alter_mvc/blob/release_1_0_0/lib/alter_mvc/helpers/controller/setting_render_context.rb):

```
AlterMvc::Config.render_context = self
```

change by:

```
AlterMvc::Config.render_context = view_context
```
