Merge branch 'hotfix/#6858-allow-zend-session-container-name-with-numeric-name-initial'

Close #6858
Added check for property existance unless object is stdClass to prevent invalid data being added
added new Test
added newline for EOF
fix for typo in test
added fix against private/protected properties when propertyExists says they exist
clean up test assertions and refer to TestAsset already available (with modification to 1 property to make protected)
repair changes to testAsset to prevent breakage of other tests. Moved to setExpectedException instead of annotation
Correction of test values in testCanExtractFromClass
Changed to not exclude non existant properties
switched check style to improve performance over reflection
streamlined ObjectProperty private/protected checks a little
reversion (partially) to Reflection again to counter php's ability to unset properties which then don't get cast to array
adding property for cache - missing from previous commit
fix for unexpected T_OBJECT_OPERATOR on 88
CS fix for array map closure
#6869 - s/`assertAttributeContains`/`assertAttributeSame` for strict checks. Minor CS, method naming and docblock fixes
#6869 - adding assertions for newly introduced properties on generic userland classes
#6869 - correcting visibility of some supposedly protected/private members
#6869 - property filter cache can be private