Pelutils

- Added append mode to logger to append to old log files instead of overwriting

- Added `ds` submodule for data science and machine learning utilities

This includes `PyTorch` utility functions, statistics, and `matplotlib` default values

- Logger now raises errors normally instead of using `throw` method

- `get_repo` now accepts a custom path search for repo as opposed to always using working dir

- `log.input` now also accepts iterables as input

For such inputs, it will return a generator of user inputs

- Added functionality to logger for logging repository commit
- Removed function `get_commit`
- Added function `get_repo` which returns repository path and commit

It attempts to find a repository by searching from working directory and upwards
- Updates to examples in `README` and other minor documentation changes
- `set_seeds` no longer returns seed, as this is already given as input to the function