reoriganized the JNI findcells method to account for the fact that C's findcells() can be called with either or both zdrImage and rhoImage equal to NULL
reoriganized the JNI findcells method to account for the fact that C's findcells() can be called with either or both zdrImage and rhoImage equal to NULL

NLeSC/enram,NLeSC/enram,NLeSC/enram,NLeSC/enram