The aim of this commit is to:

• Auto-generate names for user accounts that no longer exists. This will still
  maintain the identity of the accounts, rather than having no differentiation
  between these accounts.

• Adding the handling for mailto links when enabled in the cases where it was
  missed (history events, view all bugs page).

• config_defaults_inc.php:

• Added new configuration option: prefix_for_deleted_users which sets
  the prefix to be used for accounts that no longer exists. For example, if
  prefix is 'user' and user 32 no longer exists, then the generated name is "user32".

• doc/Changelog:

• Updated the change log.

• history_inc.php:
  (history_get_events_array):

  • Returning the user id, not just the user name.
  • Returning the auto-generated user name if the user no longer exists.

M view_all_inc.php

• Use print_user() to print the user name. This is in order to support the
  email link when enabled.

M core/history_api.php

• Using print_user() to print the user name. This is in order to support the
  email link.
• Before the user name and (account no longer exists) were not displayed if the
  user account was deleted.
  M core/user_api.php
  (user_get_name): Support auto-generation of names as per the configuration.
  M core/print_api.php
  (print_user): Changed to re-use the user_get_name() rather than handling user
  accounts that no longer exists.
  (print_user_with_subject): Changed to re-use the user_get_name() rather than
  handling user accounts that no longer exists.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1747 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9