extract WeakformProcessorFactory from WeakformProcessor, remove the NeedPreparation interface of WeakformProcessor
use setters instead of arguements of WeakformProcessor methods
fix a bug of SupportDomainSearcherFactory that makes null exception when run MLSLevelSetDemo
move most influence and support domain size relative codes from WeakformProcessorFactory to Model2D
remove 2 redundent lines of SupportDomainSearcherFactory
let Model2D holds influenceRadiusCalculator directly
extract MechanicalWeakformAssemblier interface, move setConstitutiveLaw() from WeakformAssemblier to the new interface