[ticket/12841] Allow extensions to position new config vars

PHPBB3-12841
[ticket/12841] Fix white space issues reported by sniffer

PHPBB3-12841
[ticket/12841] prefix function name with phpbb_

PHPBB3-12841
[ticket/12841] Make config position default to after

PHPBB3-12841
[ticket/12693] Remove the executable bit on icon_print.gif

PHPBB3-12693
[ticket/12831] Optn to prevent setting HTTP headers

https://tracker.phpbb.com/browse/PHPBB3-12831

PHPBB3-12831
[ticket/12778] Automatically delete files on update

PHPBB3-12778
[ticket/12778] Rename the file to *.bak instead of deleting

PHPBB3-12778
[ticket/12718] Use remove_topic_from_statistic() for delete_topic

PHPBB3-12718
[ticket/12718] Update docblock

PHPBB3-12718
[ticket/12535] Make <a> adjust to the image width

PHPBB3-12535
[ticket/12535] Add events to subsilver2

Forgot subsilver... yet again

PHPBB3-12535
[ticket/12535] Update events.md to RC3

PHPBB3-12535
[ticket/12535] Combine inner clearing CSS rules

PHPBB3-12535
[ticket/12710] Prepare get_existing_indexes() for other DBMS

PHPBB3-12710
[ticket/12880] core.mcp_queue_!is_topics_query_before

Adding core.mcp_queue_is_topics_query_before

PHPBB3-12880
[ticket/12876] core.mcp_mcp_front.mcp_front_view_queue_postid_list_after

Adding the core.mcp_mcp_front.mcp_front_view_queue_topicid_list_after
event to mcp backend.

PHPBB3-12876
[ticket/12710] Fix changing the column type on oracle

PHPBB3-12710
[ticket/12886] Remove obsolete check for f_user_lock

The user shouldn't be able to unlock his own topic if he doesn't have m_lock
permissions. Also, the check for f_user_lock was never going to evaluate to
true due to the topic not being unlocked making it obsolete anyway.

PHPBB3-12886
[ticket/12718] Fix docblocks

PHPBB3-12718