birdnetR v0.2.0

This update brings significant changes and improvements, including support for loading pre-existing and custom-trained models, aligning the package with birdnet 0.1.6.

breaking changes:

• The init_model() function is now deprecated and will be removed in the next version. Please use the birdnet_model_* function family for model initialization.
• available_languages() update: A new argument has been added to available_languages() to specify the BirdNET version, making it more flexible for different model versions.
• Renaming get_labels_path to labels_path(). It now requires a model object as its first argument.
• predict_species() was renamed to predict_species_from_audio_file()
• predict_species_at_location_and_time() was changed to requirer a model object as first argument.

New features:

• Support for Custom Models: You can now load custom-trained models
• A new set of functions (birdnet_model_*) to load pre-existing and custom-trained models. These functions offer a more flexible approach to model loading. See ?birdnet_model_load for more details.
• S3 Object-Oriented System: The models are now implemented as S3 classes, and most of the functionality related to these models is provided through methods. This update makes the API cleaner and more consistent, and allows for better extensibility in future versions.