pyicon/quickplots/qp_compare.py: Allow to use time averaged data. Adjusted color levels for difference plots.

notebooks/examp_oce_zstar.ipynb: Some expansions were made and errors corrected in the notebook examp_oce_zstar-copy1.ipynb. These fixes were never commited but now, the old notebook was replaced by the new one.

tools/pyic_sec.py: Allow pyic_sec to be used with the original ICON grids. Two grids are supported at the moment 30W and 170W.

[qp_driver_new_oce_output.py]: Helmuth's suggestions: Use old and new heat flux diagnostic. Change mld to mlotst. Allow mass_flux to be read optionally as vertical integral (new method) or as 3D field (old method).

Added config_qp/conf-r2b6_mkexp.py and config_qp/conf-r2b8_mkexp.py as examples for more variable output in particular that which comes out after mkexp manipulations.

pyicon/pyicon_IconData.py: Do not check anymore whether path_data can be found. This allows to use wildcards in path_data without getting an error.

quickplots/qp_driver_new_oce_output.py: Allow for varying association between variables and file containers.

Merge pyicon_dwd with master

See merge request !4

pyicon/pyicon_IconData.py: Moved extra clon, clat etc. loading part to DWD if block to save memory in default configuration.

[pyicon_dwd] adjust back pyicon/quickplots/qp_driver.py so that it reads global mean diagnostics (*_mon_* files) as from ICON with ECHAM physics. This is because i introduced global mean outputs to ICON-NWP.

[pyicon_dwd] add tools/prep_mon_files_dwd.sh to prepare global mean time series files from *atm_2d_ml* files

[pyicon_dwd] pyicon/quickplots/qp_driver.py: get land-sea mask from 1s output file, delete obsolete files *_dwd_*

[pyicon_dwd] update pyicon/pyicon_IconData.py pyicon/quickplots/qp_driver.py with the right content for ICON-NWP outputs