Fixed facbook login and added missing page titiles

app/views/application/404.html.haml

@@ -1,8 +1,4 @@
-- @page_title = 'page_titles.404.Page_Not_Found' unless @page_title.present?
-
 = render :partial => 'application/header', :locals => {:image_file => nil}
 = row do
 	= columns(medium: 12) do
-		%h1
-			=_'error.404.title','This page does not exist!'
-		=paragraph(_'error.404.description', :p)
+		= paragraph(_'error.404.description', :p)

app/views/application/_header.html.haml

@@ -15,4 +15,4 @@
 				=@page_title.present? ? I18n.t(@page_title, @page_title_vars) : I18n.t("page_titles.#{page_group.to_s}.#{page_key.to_s}")
 			= row do
 				= columns do
-					%h1=(_"page_titles.#{page_group.to_s}.#{page_key.to_s}")
+					%h1=_(@main_title || "page_titles.#{page_group.to_s}.#{page_key.to_s}")