Closure immutability
Update 14-classes.md
Added examples for division by zero
added notice about diagnostic
Clarify how interface/abstract method signatures may differ
add phpt test
Merge branch 'pull-request/80' into PHP-5.6
Expression fixes
Merge branch 'pull-request/83' into PHP-5.6
improve compatibility description
Merge branch 'pull-request/78' into PHP-5.6
add pr #67
pr #73
Merge branch 'expressions-fixes' into PHP-5.6
added description about object properties
Merge branch 'object-properties' of https://github.com/robstoll/php-langspec into object-properties