modified by jixie
This is Jixie's fir commit into jixie's branch
      modified:   gen_evt.f
      modified:   guout.f
      modified:   gustep.f
      deleted:    test
I cleaned some comments in gen_evt.f, also fixed several bugs in it

In guout.f I comment out a if statement which is requiring there
are hits in calorimeter in order to write an event into the ntuple.
This is temperaly change. I am trying to write all event into the
ntuple so I can do charge normalization. I will change it back
once I finish my job.

gustep.f, I added a comment. I verified that call step_tracker()
will not affect the speed.  Still need to find out why this program runs
so slow.

I remove test since it is not used any where and donot know what it is.
Tried to solve the problem that pi0 xs is 1000 times larger
than what it should be.

Changed sane_accp.inc to a reasonable range that can cover
both e- and pi0.

Put the details of my modification into file notes.txt

Added lot of comments into source code.