Added ability to read in continuous secondary energy distributions for inelastic S(a,b) collisions. Still have to implement new collision physics in physics.F90
Corrected an error message in physics.F90:sample_energy, which referred to Law 44 instead of the correct Law 61.
Added code to physics.F90%sab_scatter() to sample continuous secondary energy distributions; still have to test.
Modified code after some testing to not perform interpolation on Ein and Eout when finding mu; instead the closest distribution is chosen, as is done for file 4 angular distributions in sample_angle.
Two small fixes in installation instructions.
Make sure uvw is initialized when sampling source position.
Fix bug in convert_xsdir.py.
Allow mixed ascii/binary cross_sections.xml.
Merge remote-tracking branch 'upstream/develop' into cont_sab
Included explicit integer casting in the reading of thermal data.
Updated theory manual to incorporate the new thermal scattering sampling technique
Fixed a typo in theory documentation.
Fix particle track bug when using Intel compiler.
fixed conflict, merged develop