Ignore Hidden Files in HydPy Folders

[BGWKlein]

It would be great if HydPy could ignore hidden files starting with "." in hydpy folders when reading in network and control files.

In my HydPy directory a file naming .keep exists from version control. When reading in network files the following error occurs:

RuntimeError: The class Node cannot be loaded from the network file "c:\HydPy\HydPy-H96p-Rhein\network\default\.keep".

[tyralla]

Maybe we could also ignore all other files that are not Python files. In case someone wants to add a README.md file or something like that.

[BGWKlein]

Good idea