Small updates to docstrings

Added method to allow for the specification of an existing Guess when calling the fit function.

Updated mock list

Loop parameter extraction added
Hopefully fixed documentation

New parameter, get_loop_parameters, added to doFit and doGuess
If true, the physical loop parameters will be calculated from the guess or fit before the method returns

Scan size taken from number of image files if not provided.

PEP8 cleanup

Adds loop parameters to existing axes from plot_loop_guess_fit

Now catching correct error type.

Changed how the Channel group is located to allow for plotting of the rebuilt SHO results.

Moved some common translator activity - preparing the tree and writing it - from forc_iv to the parent translator so that it can be reused

cmap_from_rgba generates a colormap from a simple interpolation table.
cmap_hot_desaturated now uses the above function.
make_linear_alpha_cmap generates a colormap for a single color with varying transperancy.

Moved the static method __get_component_slice to processing.svd_utils._get_component_slice

Generic rebuilding of a dataset from the U, S, and V datasets from running SVD decomposition.