[dev] Refactoring: merging send_file() and send_global_file().
Now send_file() was moved to tools.pm and will take list OR robot as parameter. Exception is new method send_probe_to_user() to send welcome and remind messages using VERP. As a side work, {shelved}{tracking} attribute of messages can be "w" or "r" by which bulk.pl generates VERP sender of messages stored by send_probe_to_user(). git-svn-id: https://subversion.renater.fr/sympa/branches/sympa-6.2-branch@11332 05aa8bb8-cd2b-0410-b1d7-8918dfa770ce