checkother: improved constness of local variables, no functional change.
checkother:memsetZeroBytes: improved verbose message.
Checkother:memsetZeroBytes: removed not needed '\n' from verbose message.
AST: Added experimental new implementations for CheckAssignIf::comparison, CheckOther::checkIncorrectLogicOperator and CheckOther::checkDuplicateExpression
Fixed #5151 (false negative: improper formatstring - vector::at())
Fixed #5153 ((debug) Scope::checkVariable found variable ')')
Null pointers: Don't warn when first argument to freopen() is NULL