In some cases the emails were not sent. After investigation the problem was
found to be in the case where use_bcc = ON and to_email was sent to ''. This is
because the recipient was found to be empty and hence the email was not sent.
There was no checking for the headers to check the bcc. I added a quick fix
which can be improved later.

M .cvsignore: Added phpmailer files to the cvs ignore list.

M core/email_api.php
(email_bug_info): Changed the checking of the headers / to_email being empty
to use is_blank().
(email_send):

• Only activate shortcut to exit email_send() if recipient (to) is
  empty and bcc is OFF. For now, we assume that if bcc is ON, it will contain
  some recipients, this will need to be changed later by separating headers from
  bcc.
• Adjust the formatting of the email debug feature where extra commas were
  added at the end of the to / bcc list.
• Used is_blank() to test the $p_recipients.
• Changed include_once() for phpmailer to require_once().

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1780 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9