Ryan/dev work

[Ryan-Rhys]

Photoswitch example. Summary of changes that touch other parts of the codebase:

1. Extra flags added to kpca.py and umap_reducer.py in order to allow the usage of the Morgan fingerprint representation. Default is not to use it.

2. 'metric' flag added to gen_soap_kmat.py that allows users to specify what form of kernel they want from kpca. Default set to linear.