Added energy loss to MC
------------------------
1. Add code to calculate a random energy loss, enerloss_new.f,
taken from SIMC. To calculate the mean energy loss used the
code, engine_loss.f, which is the subroutine loss from total_eloss.f
in the RSS engine.

2. Added these codes to the Makefile.

3. Changes to mc_hms_single.f for the mean energy loss which
is copied from the engine. 

a. First the target type is determined from the target file. tartype is 
set to 1 = C+He, 2 = C, 3 = MT + He, 4= MT+ no He, 5 = NH3
and 6 = ND3. The target thickness, target density,target A,
target Z and target radiation length is taken from the param file
in the RSS engine.

b. Using the subroutine loss, the mean energy loss is calculated 
for the beam in the:
  i) Scattering chamber window
  ii) If NH3 or ND3 then 1.25cm of He or if C+He then 1.6cm of He.
  iii) Half of the target material depending on tartype.
Then the mean energy loss is subtracted from the beam energy
to and new variable ebeam_mp. ebeam_mp is used for calculating
the reconstructed kinematics.

c. Using the subroutine enerloss_new the random energy loss is
calculated for the beam:
   i) scattering chamber window
   ii) loop through each material in the target file. If
       the material is before the z position of the randomly
       chosen interaction point then use the thickness and
       density,A, and Z from the target file.
Then random energy loss is subtracted from the beam energy
in the input file and put into a new variable ebeam_ran. ebeam_ran
is used for the determine the radiative energy loss and calculation
of the event kinematics.

d. Using the subroutine enerloss_new, the random energy loss
is calculated for the scattered electron. For most targets,
it loops through the target material and for any material after
the z interaction point the energy loss is calculated. NH3 and ND3 are special
cases and depending on the z position of the interaction it calculates
the path length in the helium before the cell and the path length
in the helium after the cell. In addition the path length in
the cell is calculated. It is assumed that the packing fraction is 50%
and so that path length is divided by 2 and the random energy loss
in the NH or ND and the helium is calculated. Then the energy loss
for the tailpiece and 4K shield is calculated. For all target 
the energy loss for the  Scattering chamber window, air and 
HMS entrance window is calculated.

e. Using the subroutine loss the mean energy loss is
calculated for the scattering electron in the same
manner as the engine.
   i) Half of the target material depending on tartype.
   ii) If NH3 or ND3 then 1.25cm of He or if C+He then 1.6cm of He.
   iii) If NH3 or ND3 then cell wall.
   iv) Scattering chamber window,air and HMS window.