Resolve path issue for IMDB

Resolve path issue for IMDB dataset

Split dataset loaders

• Add support for IMDB dataset
• Define individual dataset loaders for supported datasets

Fix transform for CIFAR10

Add default transform for CIFAR10 for when the user opts for no normalization.

Update dependency on torch and torchvision

Update dependency on torch and torchvision

Fix download issue for MalImg dataset

The link to the MalImg dataset was a tuple instead of a string. This has now been rectified.

Fix n-grams range parameterization

Resolve issue n-grams range parameterization for text loading without vectorizer.

Parameterize n-grams range

Allow the customization of n-grams range to use for text vectorization.

Fix 20newsgroups vectorizer unpacking

Resolve issue on loading vectorizer for 20newsgroups dataset.

Fix return of vectorizer object

Resolve the issue on accessing and returning the vectorizer object.

Refactor 20newsgroups and AG News datasets

• Implement a torch.utils.data.Dataset class for 20newsgroups and AG News datasets.
• Load the two datasets using their respective classes.
• Remove old functions for loading the two datasets.