Added insolation on person

Also generalized the calculation for generic surface
Minor cleanup

Now all the files for one area are stored in a folder.
I have also a clear convention for the naming of the files
NIght time seelction

At night time we pass directly at calculating the temperaytures. We do
not need to check position of the sun, etc.  This speeds up the
calculations massively, but at the same time showed a bug in the
calcualtion of the view factors
Introducing the overall radiation

Adjusted the radiation from the surfaces to take into account the
temperature of the receiver
Added a few global variables

Also improved the radiation between surfaces