[ticket/12929] core.ucp_pm_compose_compose_pm_basic_info_query_before

Adding the core.ucp_pm_compose_compose_pm_basic_info_query_before
event to mcp backend.

PHPBB3-12929
[ticket/12929] Update to RC4

PHPBB3-12929
[ticket/12929] Adding more variables to event.

More variables added that may be useful to events at this stage.

PHPBB3-12929
[ticket/12929] Fixing event comment block and variable

PHPBB3-12929
[ticket/12929] BUMP to RC5

PHPBB3-12929
Merge pull request #2827 from brunoais/ticket/12929

[ticket/12929] core.ucp_pm_compose_compose_pm_basic_info_query_before