Hydpy

*HydPy* informs the user when trying to read missing or incomplete observed or simulated time series data into *Node* objects. Due to some recent changes, this feature became unreliable. Version 3.1.1 fixes this problem and adds explanations and tests to the online documentation, to (hopefully) prevent this from happening again.

*HydPy* now checks for missing values in e. g. meteorological input time series data. This behaviour can be enabled/disabled by setting option *checkseries* to True/False.

Additionally, XML file implementations of the XML schema file *config.xsd* are now easier to maintain regarding version changes and general options like *checkseries*.

From now on, installing `matplotlib` is not required for using (most features of) `HydPy` anymore.

For convenience, XML namespaces are now valid download links, and some name discrepancies result in warnings only instead of errors.

One can now manually define the name and style of log files when executing workflows based on XML configuration files.

From now on, version specific XML schema files will be part of each new HydPy release, making referencing them more comfortable.

These changes do not fix actual bugs but simplify coupling with Delft-FEWS.

Read from and write into flat archives, e.g. `LahnHBV/conditions/init_start.zip/land_dill.py` instead of `LahnHBV/conditions/init_start.zip/init_start/land_dill.py`.

This change does not fix an actual bug but simplifies coupling with Delft-FEWS.