Some features to be added in PyGAD 2.15.0

1. Control the precision of all genes/individual genes. Thanks to [Rainer](https://github.com/rengel8) for asking about this feature: #43 (comment)

2. A new attribute named `last_generation_parents_indices` holds the indices of the selected parents in the last generation.

3. In adaptive mutation, no need to recalculate the fitness values of the parents selected in the last generation as these values can be returned based on the `last_generation_fitness` and `last_generation_parents_indices` attributes. This speeds-up the adaptive mutation.

4. When a a sublist has a value of `None` in the `gene_space` parameter (e.g. `gene_space=[[1, 2, 3], [5, 6, None]]`), then its value will be randomly generated for each solution rather than being generated once for all solutions. Previously, a value of `None` in a sublist of the `gene_space` parameter was identical across all solutions.

5. A new function called `predict()` is added in both the `pygad.kerasga` and `pygad.torchga` modules to make predictions. This makes it easier than using custom code each time a prediction is to be made.

6. A new parameter called `stop_criteria` allows the user to specify one or more stop criteria to stop the evolution based on some conditions. Each criterion is passed as `str` which has a stop word. The current 2 supported words are `reach` and `saturate`. `reach` stops the `run()` methof if the fitness value is equal to or greater than a given fitness value. An example for `reach` is `"reach_40"` which stops the evolution if the fitness is >= 40. `saturate` means stop the evolution if the fitness saturates for a given number of consecutive generations. An example for `saturate` is `"saturate_7"` which means stop the `run()` method if the fitness does not change for 7 consecutive generations. Thanks to [Rainer](https://github.com/rengel8) for asking about this feature: #44

Author: ahmedfgad