Release v1.4.18

Add total in-alter continuous effect support

Introduces the ability to compute total in-alter values (not averaged) for continuous effects by adding a constructor argument divide=false (default divide=true)to AverageInAlterContinuousEffect and updating EffectFactory to use it for 'totInAlt'. This is what the RSiena authors chose to do with respect to discrete behaviour variables to reduce redundant C++ effects for mathematically near-equivalent effects. Could revisit my other custom effects to see if the same logic applies elsewhere.

Also updates allEffects.csv to register new effect types totWInAlt (was already implemented, but not made available here) and totInAlt.