Tomobar

Added

Vector geometry added to 3D case replacing the scalar aproach
Center of Rotation (CenterRotOffset variable) can be defined in the class as a scalar to avoid direct data manupulations (cropping, padding)

Changed

Demos for 2D/3D reconstruction updated with a new class

Removed

Section about "changelog" vs "CHANGELOG".

Removes the unnecessary C code from the source and enables pyproject.toml packaging

- A new and much concise structure for ASTRA wrappers [here](https://github.com/dkazanc/ToMoBAR/blob/master/src/Python/tomobar/supp/astraOP.py)
- MultiGPU capability to control GPU devices with a [demo](https://github.com/dkazanc/ToMoBAR/blob/master/Demos/Python/MultiGPU_demo.py). Note that the latest CCPi-Regularisation package is required to run iterative reconstruction with MultiGPU support