Detect when there are no pdepColliderReactions.
Detect when there are no pdepColliderReactions.

Fix bug in if statement.  A numpy array with a [0] fails the if statement.

chatelak/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py,nyee/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py