list of PropertyUsage's (use, consume) that cannot have a FPValueProvider
improvements to src/main/java/org/amplafi/flow/flowproperty/ReflectionFlowPropertyValueProvider.java
FlowPropertyDefinitionBuilder: handles initFlowPropertyValueProvider and initFlowPropertyValuePersister with null arguments to allow clearing previously set values.
better handling of PropertyUsage.use/consume when there is also a FlowPropertyValueProvider