Allow SelectorExpr as RenderArgs

[viblo]

Allows code like

func (c MyController) Index() revel.Result {
    return c.Render(myotherpackage.Data)
}

<p>my data is: {{.myotherpackage_Data}}</p>

[jeevatkm]

@viblo Thanks for contributing to Revel. Sorry for delayed response.

Can you please help out with following-

• Please target the develop branch per Revel's Contributing Guidelines
• Documentation about how to use this new feature
• Test case for SelectorExpr

[viblo]

@jeevatkm Im currently working on other things but will take a look at this and fix my PR next time I work with revel related functionality.

[jeevatkm]

@viblo Thanks for your response. I will do what I can.