Scripting: Mass Mailer Updates

I've made a few relatively minor updates to the mass mailing script.

• I noticed that the sender address entered on the form was not reflected in the actual e-mail sent out. Turns out I forgot to add a parameter/replacement for this value in the e-mail templates. This oversight has been corrected.
• Added a check for sender and subject so that default information could be added if necessary.
• Updated the EOL fix in the fnc_qpEncode() function so that it is a bit more streamlined.
• Updated the BOL period replacement to place the encoded period on a line by itself. This was necessary to avoid line length overflow.
  
• Updated the recipient replacement code to run in two stages. The first stage replaces the recipient information in the body of the message an encodes it using quoted printable. This helps avoid line length overflow on long e-mail addresses. (This code is in addition to code from fnc_qpEncode() that places any placeholder variables on a line by themselves.) The second stage replaces any other occurrences of the recipient address placeholder, which should be just in the message header.