### SLA_VN

Normalize Vector

ACTION:
Normalize a 3-vector, also giving the modulus (single precision).
CALL:
CALL sla_VN (V, UV, VM)
##### GIVEN:
 V R(3) vector

##### RETURNED:
 UV R(3) unit vector in direction of V VM R modulus of V

NOTE:
If the modulus of V is zero, UV is set to zero as well.