Allow decimals in number of properties assigned to customer points

When setting up future demand scenarios we are often provided increase in population over an existing area of the network, reflecting infill growth across the area. However we can't distribute this across existing customer points because only a whole number of properties can be assigned to each customer point. Demand scaling could be used for this but has a number of drawbacks: - To use demand scaling we need to change the area code to reflect development areas, which means we can't use area codes to analyse DMAs. - It also means the demand statistics for a network does not include infill growth and does not represent actual demand. - it means we can't use demand scaling for any other purposes. We can leave the number of properties unchanged and increase the specific consumption for each property - the demand statistics will have the correct demand but will have the wrong number of properties. The most common thing we are asked is "how many properties are affected?", so this is no good. So, we need the ability to assign e.g. 1.05 properties to a customer point. Thanks, Ben