New params in dict and base64 encoded strings in LargeBinary

0.10.7

✨ Features

• Add exclude_primary_keys: bool = False flag to dict() method that allows to exclude all primary key columns in the resulting dictionaru. #164
• Add exclude_through_models: bool = False flag to dict() that allows excluding all through models from ManyToMany relations #164
• Add represent_as_base64_str: bool = False parameter that allows conversion of bytes LargeBinary field to base64 encoded string. String is returned in dict(),
  on access to attribute and string is converted to bytes on setting. Data in database is stored as bytes. #187
• Add pk alias to allow field access by Model.pk in filters and order by clauses (python style)

🐛 Fixes

• Remove default None option for max_length for LargeBinary field #186
• Remove default None option for max_length for String field

💬 Other

• Provide a guide and samples of dict() parameters in the docs
• Major refactor of getting/setting attributes from magic methods into descriptors -> noticeable performance improvement