Adding tests/fixes for possible XSS injections in view helpers

Signed-off-by: Marco Pivetta <ocramius@gmail.com>
[ZF2014-03] Added detail to README.md
Merge branch 'security/zf2014-03'

ZF2014-03 fixes
[2.3.1] Release readiness

- Updated README with version, date, and changelog
- Updated CHANGELOG with 2.3.1 and 2.2.7 details
- Updated version constant to 2.3.1
Merge branch 'releases/2.3.1'

2.3.1 release readiness
Release bump: 2.3.2dev
Merge branch 'release/bump'

2.3.2dev
Add fail test case
Fix collection with element validation
Add error message assertion
Add assertion with fieldset inside collection
SessionManager fails validation on listeners that do not perform any operation
Session validator listeners should strictly fail when returning `false`
Merge branch 'Ocramius-hotfix/session-validation-listeners-null-return-values'

Close #6147
Zend\Db\Sql
- Fixed AbstractSql's processSubSelect to use decorators when calling getSqlString()
Merge branch 'ralphschindler-hotfix/5794'
Merge pull request #6141 from localheinz/bugfix/indentation

Fix: Indentation of method arguments
Merge branch 'hotfix/6141'

Close #6141
Merge pull request #6146 from blanchonvincent/hotfix/collection-with-element-validation

Collection validation with element as target element
Merge branch 'hotfix/6146'

Close #6146
Fixes #6115