Clean up view helpers, aka fix bugs by following convention

* don't nest view helpers in module for no reason
* rename view helpers per the convention
* add explicit csrf tags helper instead of applicationhelper
* isolate_namespace !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

app/helpers/adminsimple/flash_helper.rb

@@ -0,0 +1,17 @@
+module Adminsimple
+  module FlashHelper
+    def flash_messages
+      messages = ''
+      [:alert, :notice].each do |prop|
+        messages << flash_message(prop) if flash[prop].present?
+      end
+      messages.html_safe
+    end
+
+    def flash_message(prop = :notice)
+      close_button = content_tag(:button, '&times;'.html_safe, class: 'close', data: {dismiss: 'alert'})
+      content = content_tag(:strong, "#{prop.to_s.titleize}! ") + flash[prop]
+      content_tag(:div, "#{content}#{close_button}".html_safe, class: "alert alert-#{prop}")
+    end
+  end
+end

app/helpers/adminsimple/page_header_helper.rb

@@ -0,0 +1,11 @@
+module Adminsimple
+  module PageHeaderHelper
+    def page_header(options = {}, &block)
+      options[:id] ||= "adminsimple_page_header"
+      options[:title] ||= controller.controller_name.to_s
+      content = block ? capture(&block) : nil
+      locals = {content: content, title: options.delete(:title)}
+      content_tag(:div, render(partial: 'adminsimple/modules/page_header', locals: locals), options)
+    end
+  end
+end

app/helpers/adminsimple/rescued_csrf_meta_tags_helper.rb

@@ -0,0 +1,10 @@
+module Adminsimple
+  module RescuedCsrfMetaTagsHelper
+    def rescued_csrf_meta_tags
+      csrf_meta_tags
+    rescue ArgumentError
+      request.reset_session
+      csrf_meta_tags
+    end
+  end
+end

app/helpers/adminsimple/widget_box_helper.rb

@@ -0,0 +1,23 @@
+module Adminsimple
+  module WidgetBoxHelper
+    def widget_box(options = {}, &block)
+      options[:class] = options[:class] ? "#{options[:class]} adminsimple-widget-box" : 'adminsimple-widget-box'
+
+      if options[:icon] == :checkbox
+        options[:icon] = content_tag(:input, '', type: 'checkbox')
+      elsif options[:icon].present?
+        options[:icon] = content_tag(:i, '', class: "icon-#{options[:icon]}")
+      end
+
+      if options[:label].is_a?(Hash)
+        labels = options[:label].map { |key, value| content_tag(:span, value, class: "label label-#{key}") }
+        options[:label] = labels.join('').html_safe
+      elsif options[:label].present?
+        options[:label] = content_tag(:span, options[:label], class: 'label')
+      end
+
+      locals = {content: capture(&block), title: options.delete(:title), icon: options.delete(:icon), label: options.delete(:label)}
+      content_tag(:div, render(partial: 'adminsimple/modules/widget_box', locals: locals), options)
+    end
+  end
+end

lib/adminsimple/rails/engine.rb

@@ -2,18 +2,6 @@
 
 module Adminsimple
   class Engine < ::Rails::Engine
-    engine_name 'adminsimple'
-
-    initializer "adminsimple.view_helpers" do
-
-      ActiveSupport.on_load :action_view do
-        Rails.application.reloader.to_prepare do
-          ActionView::Base.send :include, Adminsimple::ViewHelpers
-          ActionView::Base.send :include, Adminsimple::Modules::WidgetBoxHelpers
-          ActionView::Base.send :include, Adminsimple::Modules::PageHeaderHelpers
-        end
-      end
-    end
-
+    isolate_namespace Adminsimple
   end
 end