improve partials recipe to include more nuanced/complex variations 

beefin up the partials recipe using stuff from 'I Did It My Way'[1] and "Padrino'[2]

[1] https://github.com/daz4126/I-Did-It-My-Way-Partials
[2] https://github.com/padrino/padrino-framework/blob/master/padrino-helpers/lib/padrino-helpers/render_helpers.rb