[ticket/11782] Change p.rules to p.post-notice in templates

PHPBB3-11782
[ticket/11782] Change p.rules to p.post-notice in CSS

PHPBB3-11782
[ticket/11782] RTL support for post notices

PHPBB3-11782
[ticket/11782] Apply line-height correctly

Apply line-height only to bolded elements inside post notices
that are direct child elements of forms.

PHPBB3-11782
[prep-release-3.0.12] Bumping version number for 3.0.12-RC3.
[prep-release-3.0.12] Update Changelog for 3.0.12-RC3 release.
Merge branch 'prep-release-3.0.12' into develop-olympus

* prep-release-3.0.12:
  [prep-release-3.0.12] Update Changelog for 3.0.12-RC3 release.
  [prep-release-3.0.12] Bumping version number for 3.0.12-RC3.

Conflicts:
	phpBB/includes/constants.php
	phpBB/install/database_update.php
	phpBB/install/schemas/schema_data.sql
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [prep-release-3.0.12] Update Changelog for 3.0.12-RC3 release.
  [prep-release-3.0.12] Bumping version number for 3.0.12-RC3.

Conflicts:
	build/build.xml
	phpBB/install/database_update.php
Merge pull request #1651 from cyberalien/ticket/11782

Fix layout of notices in posts
Merge remote-tracking branch 'upstream/develop' into develop