Based on r6226 from Redmine by Jean-Philippe Lang

Instead of a single email that is sent out with all the recipients as CC/BCC,
each recipient will be delivered their own email. This will let emails to be
customized per user based on their permissions, without exposing private data.

[#388] Custom LDAP filter

These filters change the implemntation of sub and gsub to use the block method.
This prevents the evaluation of backreferences in the replacement text. See
https://gist.github.com/1491437 for examples.

Also, it allows split to be called without arguments to split strings on
whitespace.