replaces nested content_for and layouts by partials composition
refactor user#show to use partials composition
Merge branch 'maps' into views-with-partials

Conflicts:
	app/helpers/users_helper.rb
refactor user#edit to use partials
remove polymorphic layout
simplify object rendering
small refactor on helper method names
render contributions/contributors with parent object layout
spesc and fixes
introduce presenters to clean helpers mess + ToolbarPresenter
fix specs and add specs to presenters
object_presenter for generic object rendering
fix broken specs and add some documentation
remove unnecessary required key + change presenter to be a concern
object_presenter specs
added some code docs
add maps_controller
maps#show