Dataclass-csv

* Added support for boolean values.
* Docstrings

* Fixed issue when parsing headers on a CSV file with trailing white spaces.

* When a data does not pass validation it shows the line number in the CSV file where the data contain errors.
* Improved error handling.
* Changed the usage of the `accept_whitespaces` decorator.
* Updated documentation.

* Added support for default values from `default_factory` in the field's metadata. This allows adding mutable default values to the dataclass properties.

* Added support for reader default values from the default property of the `dataclasses.field`.
* Added support for allowing string values with only white spaces in a class level using the `accept_whitespaces` decorator or through the `dataclasses.field` metadata.
* Added support for specifying date format using the `dataclasses.field` metadata.

* Support for parsing datetime values.
* Better handling when default values are set to `None`