[Building Sakai] Mailsender changes and updates

[Seth Theriault]

Hello,

For anyone using Mailsender, the proposed replacement for the
now-deprecated Mailtool, there are some changes occurring that
you should be aware of:

1) The location of the Mailsender Subversion repository has
changed. Mailsender now has its own contrib space:

https://source.sakaiproject.org/contrib/mailsender

2) The previous trunk has been abandoned and will be replaced by
a new version based on 1.4 branch shortly.

3) The new trunk will form the basis for future updates. It will
include a single code base for pre-K1 and K1 installations.

Further details will be forthcoming as necessary.

Seth