fixes #2105

Also fix bug where sources were not escaped at all on post versions page

app/helpers/application_helper.rb

@@ -1,6 +1,8 @@
 module ApplicationHelper
   def wordbreakify(string)
-    raw(string.gsub(/(.{10})/, "\\1<wbr>"))
+    lines = string.scan(/.{1,10}/)
+    wordbreaked_string = lines.map{|str| h(str)}.join("<wbr>")
+    raw(wordbreaked_string)
   end
 
   def nav_link_to(text, url, options = nil)

app/helpers/posts_helper.rb

@@ -19,11 +19,11 @@ module PostsHelper
 
   def post_source_tag(post)
     if post.source =~ %r!http://img\d+\.pixiv\.net/img/([^\/]+)/!
-      text = "pixiv/<wbr>#{wordbreakify($1)}"
+      text = "pixiv/<wbr>#{wordbreakify($1)}".html_safe
       source_link = link_to(text, post.normalized_source)
       source_search = "source:#{text}/"
     elsif post.source =~ %r!http://i\d\.pixiv\.net/img\d+/img/([^\/]+)/!
-      text = "pixiv/<wbr>#{wordbreakify($1)}"
+      text = "pixiv/<wbr>#{wordbreakify($1)}".html_safe
       source_link = link_to(text, post.normalized_source)
       source_search = "source:#{text}/"
     elsif post.source =~ %r{\Ahttps?://}