ENSO version 2.0 (#8)

New in `ENSO` version 2.0:

- added information on the rotamer numbers (degeneracies gi) which enter into the Boltzmann weighting (the degeneracies can be  determined by `crest` in the version 2.10.1)
- added GFN-FF for fast calculation of  thermostatistical contributions to free energy or gbsa_gsolv as an additive solvation contribution (this requires `xtb` in the version 6.3.0 or above)
- new default settings, it is therefore advised to update your global configuration file (.ensorc)
- more functionals available for chemical shift calculation (including pre-calculated tabulated reference values) e.g. kt2, pbeh-3c,  wb97x, dsd-blyp.
- the temperature is provided to `ANMR` via the .anmrrc file                                                                          
- the final ensemble after Boltzmann weighting is written to the files populated-conf-part3_G.xyz and  populated-conf-part3.xyz which are sorted by free energy and energy
- during the ENSO run the files part1_energies.dat, part2_free_energies.dat and part3_free_energies.dat are written, for easier visualization of calculation results.
- based on the file enso.json an only printout mode is introduced (./enso.py --printout), which produces the files partx_energies.dat while only reading data from enso.json (this does only work for ENSO versions >= 2.0)
- for comparison of the solvation contributions, smd_gsolv has been introduced as additive solvation model, using the functional of  geometry optimization used in part1 and/or part2
- improved input handling 


The plotting tool `nmrplot.py` is updated to version 1.1, and is now showing minor yticks and output into svg format.

`ANMR` in version 3.5.1 fixes read error of anmr_nucinfo, reads temperature from .anmrrc and uses degeneracy information for Boltzmann calculation.

Documentation will be provided soon.

README.md

@@ -1,3 +1,5 @@
+[![Latest Version](https://img.shields.io/github/v/release/grimme-lab/enso)](https://github.com/grimme-lab/enso/releases/latest)
+
 ENSO program
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