Update installation.rst

updated installation instruction [skip ci]
Update installation.rst

fixed installation docu
gui fix
Merge pull request #61 from ssim/gui-fix

gui fix
finally implemented no configtype in yaml file. will come back when needed.
fixed missing zeta data problem [skipci]
switched over to configuration descriptions in paper1 - ionization, excitation and updated in code
change to make the values more like the paper
fix to setup2.py
fixed setup.py to new astropy setup
added new setuptools thingies