Refactored generation of unique tags, URIs and object URLs into own classes,

as well as formatting of content

app/views/notification_mailer/follow.text.erb

@@ -2,4 +2,4 @@
 
 <%= @account.acct %> is now following you!
 
-<%= url_for_target(@account) %>
+<%= TagManager.instance.url_for(@account) %>

app/views/notification_mailer/mention.text.erb

@@ -4,4 +4,4 @@ You were mentioned by <%= @status.account.acct %> in:
 
 <%= strip_tags(@status.content) %>
 
-<%= url_for_target(@status) %>
+<%= TagManager.instance.url_for(@status) %>