Changes in 2.19

[Joel Peshkin]

All:

     When developing new code for the 2.19 branch, please be aware that 
Bugzilla->user will ALWAYS be defined even if no user is logged in.(bug 
253588)  Bugzilla->user->id will be non-zero only if a user is logged 
in.  Functions controlling user access permissions can now move from 
globals.pl to User.pm have one extremely fast implementation.

    Similarly, templates checking for login should use {% IF user.id %] 
instead of [% IF user %]

-Joel