Improve needToDup: use DeepConst to determine whether dup can be ignored because all referenced data is const anyway.

• Fix #22

• Fixes bug where null ~ NullableTypeArray prepends a null value to the array.

• Deprecate @RefRead
• Update README
• Fix bug where @Read on arrays wasn't working with const objects
• Add support for dmd 2.075.1 - 2.078.0

• Add support for dmd 2.074.1 - 2.077.1
• Add annotations for generated methods

• Updated for dmd 2.073
• Debug mode was fixed

• Inheritance support added
• Generated accessors are now @properties