Add fix to angle_between function so that it will use the right values
Add fix to angle_between function so that it will use the right values

The min/max values for the exception were flipped. This resulted in the
function always returning -math.acos(-1) if it hit the exception instead
of the correct value.

crcollins/chemtools-webapp,crcollins/chemtools-webapp,crcollins/chemtools-webapp,crcollins/chemtools-webapp,crcollins/chemtools-webapp