new npa spatial weight calculation
check chord id before doing unnecessary calculations
forgot to take out some sanity checks
more npa, new method of normalizing fbm
fidasim.f90 uses entire spatial npa los weight function instead of just the weights along a line of sight
remove vestigial code
tweaks to npa_wght calculation
changes to accomendate changes made to npa weight calculation
Merge branch 'npa_wght' of github.com:D3DEnergetic/FIDASIM into npa_wght
Initial work to make fidasim work with more than one NPA chord.

Changed criteria for determining if a neutral particle hit the detector. Now
must hit aperture and detector.
fixed errors. now compiles
passes initial inspection
changed all tabs to spaces
small formatting errors caused by prev. commit fixed
add current mode
integrate over detector area
account for gyro radius
integrate over polar coor.
Merge branch 'npa_wght' of github.com:D3DEnergetic/FIDASIM into npa_wght
try using shadow area instead of prob of hit det. from isotropic source