mass_contact 5.x-2.1

Attention: Don't use the 5.x-2.1 version. It was created based on an older version of the code and does not have all the changes that were in up to 5.x-1.5.

New features as requested by the users, including:

• Force Bcc field to avoid unwanted address disclosure
• !user sent out a mail from !site.
• Please allow multiple recipients [patch]
• Setting default values for "Your name" and "Your e-mail address"
• Signature