Clean and remove empty lines (#844)

## Description
Clean and remove empty lines by Rubocop.

lib/draper/decoratable.rb

@@ -48,7 +48,6 @@ module Draper
     end
 
     module ClassMethods
-
       # Decorates a collection of objects. Used at the end of a scope chain.
       #
       # @example

lib/draper/decorated_association.rb

@@ -1,7 +1,6 @@
 module Draper
   # @private
   class DecoratedAssociation
-
     def initialize(owner, association, options)
       options.assert_valid_keys(:with, :scope, :context)
 
@@ -30,6 +29,5 @@ module Draper
 
       @decorated = factory.decorate(associated, context_args: owner.context)
     end
-
   end
 end

lib/draper/finders.rb

@@ -3,7 +3,6 @@ module Draper
   # do not have to extend this module directly; it is extended by
   # {Decorator.decorates_finders}.
   module Finders
-
     def find(id, options = {})
       decorate(object_class.find(id), options)
     end

lib/draper/helper_proxy.rb

@@ -2,7 +2,6 @@ module Draper
   # Provides access to helper methods - both Rails built-in helpers, and those
   # defined in your application.
   class HelperProxy
-
     # @overload initialize(view_context)
     def initialize(view_context)
       @view_context = view_context

lib/draper/lazy_helpers.rb

@@ -3,13 +3,11 @@ module Draper
   # so that you can stop typing `h.` everywhere, at the cost of mixing in a
   # bazillion methods.
   module LazyHelpers
-
     # Sends missing methods to the {HelperProxy}.
     def method_missing(method, *args, &block)
       helpers.send(method, *args, &block)
     rescue NoMethodError
       super
     end
-
   end
 end

lib/draper/undecorate.rb

@@ -6,7 +6,7 @@ module Draper
       object
     end
   end
-  
+
   def self.undecorate_chain(object)
     if object.respond_to?(:decorated?) && object.decorated?
       undecorate_chain(object.object)

lib/draper/view_context/build_strategy.rb

@@ -2,7 +2,6 @@ module Draper
   module ViewContext
     # @private
     module BuildStrategy
-
       def self.new(name, &block)
         const_get(name.to_s.camelize).new(&block)
       end
@@ -51,7 +50,6 @@ module Draper
           ActionController::TestRequest.method(:create).parameters.first == [:req, :controller_class]
         end
       end
-
     end
   end
 end

lib/draper/view_helpers.rb

@@ -5,7 +5,6 @@ module Draper
     extend ActiveSupport::Concern
 
     module ClassMethods
-
       # Access the helpers proxy to call built-in and user-defined
       # Rails helpers from a class context.
       #
@@ -14,7 +13,6 @@ module Draper
         Draper::ViewContext.current
       end
       alias_method :h, :helpers
-
     end
 
     # Access the helpers proxy to call built-in and user-defined
@@ -32,6 +30,5 @@ module Draper
       helpers.localize(*args)
     end
     alias_method :l, :localize
-
   end
 end

spec/draper/collection_decorator_spec.rb

@@ -7,7 +7,6 @@ module Draper
 
     describe "#initialize" do
       describe "options validation" do
-
         it "does not raise error on valid options" do
           valid_options = {with: Decorator, context: {}}
           expect{CollectionDecorator.new([], valid_options)}.not_to raise_error
@@ -287,6 +286,5 @@ module Draper
         expect(decorator.replace([:foo, :bar])).to be decorator
       end
     end
-
   end
 end

spec/draper/decoratable_spec.rb

@@ -3,7 +3,6 @@ require 'support/shared_examples/decoratable_equality'
 
 module Draper
   describe Decoratable do
-
     describe "#decorate" do
       it "returns a decorator for self" do
         product = Product.new
@@ -232,6 +231,5 @@ module Draper
         end
       end
     end
-
   end
 end

spec/draper/decorated_association_spec.rb

@@ -2,7 +2,6 @@ require 'spec_helper'
 
 module Draper
   describe DecoratedAssociation do
-
     describe "#initialize" do
       it "accepts valid options" do
         valid_options = {with: Decorator, scope: :foo, context: {}}
@@ -79,6 +78,5 @@ module Draper
         end
       end
     end
-
   end
 end

spec/draper/factory_spec.rb

@@ -2,7 +2,6 @@ require 'spec_helper'
 
 module Draper
   describe Factory do
-
     describe "#initialize" do
       it "accepts valid options" do
         valid_options = {with: Decorator, context: {foo: "bar"}}
@@ -88,11 +87,9 @@ module Draper
         end
       end
     end
-
   end
 
   describe Factory::Worker do
-
     describe "#call" do
       it "calls the decorator method" do
         object = double
@@ -246,6 +243,5 @@ module Draper
         end
       end
     end
-
   end
 end