[ticket/12132] Add viewtopic_print_head_append event to subsilver2

PHPBB3-12132
[ticket/12132] Add the event to events.md doc

PHPBB3-12132
[ticket/12134] Add ucp_pm_viewmessage_print_head_append event to subsilver2

PHPBB3-12134
[ticket/12136] Use new pagination class in generate_smilies().

PHPBB3-12136
[ticket/11880] Break up schema changes in the migrator

PHPBB3-11880
[develop] Remove left over conflict marker from merge 1a31f03
[ticket/12163] Use posts_per_page to calculate current page in viewtopic.php

PHPBB3-12163
Merge pull request #2004 from prototech/ticket/12163

[ticket/12163] Use posts_per_page to calculate current page in viewtopic.php

* prototech/ticket/12163:
  [ticket/12163] Use posts_per_page to calculate current page in viewtopic.php
[prep-release-3.1.0-a3] Update version to 3.1.0-a3
[prep-release-3.1.0-a3] Add migration for 3.1.0-a3
[prep-release-3.1.0-a3] Prepare Changelog
[ticket/11880] Move get_schema_steps function to a migrator helper class

PHPBB3-11880
[prep-release-3.1.0-a3] Commit changelog for 3.1.0-a3
[ticket/11880] migration helper file

PHPBB3-11880
Merge pull request #1995 from EXreaction/ticket/11880

Schema changes can take too long and cause a timeout
[prep-release-3.1.0-a3] Update version to 3.1.0-a4-dev for future development
Merge branch 'prep-release-3.1.0-a3' into develop
[ticket/12115] Convert user occupation to a profile field

PHPBB3-12115
[ticket/12115] Add language entries for the profile fields

PHPBB3-12115
[ticket/12115] Remove occupation field from html files

PHPBB3-12115