FIX Privilege escalation through Group hierarchy setting (SS-2013-003)

See http://www.silverstripe.org/ss-2013-003-privilege-escalation-through-group-hierarchy-setting/
FIX Privilege escalation through APPLY_ROLES assignment (SS-2013-005)

See http://www.silverstripe.org/ss-2013-005-privilege-escalation-through-apply-roles-assignment/
FIX Disallow permissions assign for APPLY_ROLES (SS-2013-005)

See http://www.silverstripe.org/ss-2013-005-privilege-escalation-through-apply-roles-assignment/
Retain 5.2 compatibility in DirectorTest

parse_url() doesn't support schema-less URLs in 5.2
Tagged 2.4.12
Failed login message translation fallback

Without this, if you use a locale with no translation for this (e.g. en_NZ), users will never see a "failed login" message.
Merge pull request #2421 from ss23/patch-1

Failed login message translation fallback
Added 2.4.12 changelog
API Escape form validation messages (SS-2013-008)
FIX Auto-escape titles in TreeDropdownField

Related to SS-2013-009. While the default "TreeTitle" was escaped
within the SiteTree->TreeTitle() getter, other properties like SiteTree->Title
weren't escaped. The new logic uses the underlying casting helpers
on the processed objects.
Merge pull request #2451 from chillu/pulls/escape-2.4

Escaping 2.4
Added 2.4.13 changelog
Tagged 2.4.13
Merge tag '2.4.12' into 2.4
Merge tag '2.4.13' into 2.4
Fix empty $messageBlock on CheckboxFields

From 2.4.13 the Message attribute is set to Text, so every checkbox now show an empty $messageBlock,
See https://github.com/silverstripe/silverstripe-framework/issues/2489 or http://www.silverstripe.org/general-questions/show/25254
Merge pull request #2716 from gbonanome/patch-1

Fix empty $messageBlock on CheckboxField
BUGFIX: URL '/' ending up beeing redirected to '//'
Merge pull request #2728 from xini/2.4

BUGFIX: URL '/' ending up beeing redirected to '//'
BUG: Stop undefined error for $reEnableFilter being thrown

NEW: Switched reEnsbleFilter fix to match coding convention