PEP8 and fix various flake8 warnings

Please, double check carefully this PR I made during my break :)

Note : 
These two items are not fixed:
  1 utilfuncs.py|59 col 19| F821 undefined name 'gauss'                                                                                                
  2 utilfuncs.py|67 col 19| F821 undefined name 'gauss_area'