Add a deprecated comments and log messages for next major release

[peter-gribanov]

• Use variable-length argument lists in next major;
• Mark bitwise operands as deprecated;
• Mark BaseSpecification::getSpec() method as abstract in 2.0;
• Mark Happyr\DoctrineSpecification\Specification\Having class as deprecated.
• The Happyr\DoctrineSpecification\Logic\LogicX class will be marked as abstract in 2.0.
• The Happyr\DoctrineSpecification\Filter\Comparison class will be marked as abstract in 2.0.
• The protected properties will be marked as private in 2.0