Dantro

- !178 extends the `count_unique` data operation to be applied along dimensions
- !174 fixes the handling of NaN values by the data operation `count_unique`
- !175 adjusts the `PlotManager` to allow UNIX shell wildcards in `plot_only` and gives more informative errors when unsupported characters are used in the plot name.
- !176 allows showing per-operation profiling statistics during DAG result computation, controlled by the `TransformationDAG.verbosity` attribute.
- !177 adds the `recursive_getitem` data operation
- !179 adds commonly-used builtin operations, e.g. `any` and `all`
- !180 adds the `ParamSpaceStateGroup.coords` property, allowing to retrieve the coordinates within the associated parameter space.
Furthermore, a [documentation entry on the `ParamSpaceGroup`](https://dantro.readthedocs.io/en/latest/data_structures/groups/psp.html) is added.

Features and Improvements
- !170 adds an [integration guide](https://dantro.readthedocs.io/en/latest/integrating.html) to the documentation, illustrating how a dantro-based data processing pipeline can be built and integrated into a project.
- !158 allows the loading of external property data in the ``GraphGroup`` (145).
- Extension of the [`data_ops` module](https://dantro.readthedocs.io/en/latest/data_io/data_ops.html):
- !161 extends the operations database with commonly used operations and makes operations on `np.`, `xr.` and `scipy.` modules easier.
- !160 adds the `expression` operation for evaluating [`sympy`](https://www.sympy.org/en/index.html) expressions
- !165 adds the `lambda` operation, which can be used to define callables, and the [`curve_fit`](https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.curve_fit.html) operation that requires such a callable.
- !168 adds the `expand_object_array` operation, allowing to unpack an `object`-dtype array of arrays into a higher-dimensional array.
- Various [transformation framework](https://dantro.readthedocs.io/en/latest/data_io/transform.html) improvements:
- !164 extends the [DAG minimal syntax](https://dantro.readthedocs.io/en/latest/data_io/transform.html#minimal-syntax) to allow specifying both positional and keyword arguments.
- !160 adds [DAG syntax parsers](https://dantro.readthedocs.io/en/latest/data_io/dag_op_hooks.html) that can simplify DAG specification.
Currently, this includes only a parser for the `expression` operation (149).
- !166 adds [DAG usage examples](https://dantro.readthedocs.io/en/latest/data_io/examples.html) to the documentation.
- !169 adds various improvements to the plotting framework:
- Allow debugging individual plot configurations using the `debug` option in the plot configuration.
- Improve error messages in `PlotManager`
- Can now control the `PlotHelper`'s behaviour upon exceptions
- The `PlotManager.plot_from_cfg` method is now also ignoring plot configurations with names starting with `.` (additionally to those starting with `_`)
- Add a [plot configuration reference](https://dantro.readthedocs.io/en/latest/plotting/plot_cfg_ref.html) page to the documentation
- !171 allows to use `load_yml` and `write_yml` with paths that include the `~` to specify the current user's home directory.


Bug fixes
- !158 fixes a bug (151) which led to edge property data not being associated correctly with the edges.
- !169 addresses 161, which prohibited specifying `out_dir` when plotting using `PlotManager.plot_from_cfg`.

- !159 fixes a bug (147) which led to duplicate DAG cache files after a storage function error.

- !151 adds documentation of the `GraphGroup`.

- !153 adds the DAG-based generic `facet_grid` plot function that wraps [`xarray.plot`](http://xarray.pydata.org/en/stable/plotting.html) functionality and makes plots of high-dimensional data very convenient.
- !157 extends the `facet_grid` plot function with animation support.
This makes it possible to represent one further data dimension via the ``frames`` specifier.
- More information can be found in [the documentation](https://dantro.readthedocs.io/en/latest/plotting/plot_functions.html).
- !154 adds the possibility to dynamically enter or exit animation mode from any `ExternalPlotCreator`-managed plot function.
- !155 addresses a bug (141) that prohibited passing containers during initialization of `LabelledDataGroup` objects or objects of derived classes.

- !152 addresses a bug (138) that prohibited using the short syntax in the `select_and_combine` field of the `MultiversePlotCreator`