Feature/a in phas a distinct style

'hasPart' is an unfortunate property name that comes from using EARL. I haven't used any of the getter/setter methods that Quail is using because they make it quite complicated to use the standard tools JavaScrips has for object/array processing such as forEach/map/reduce loops or $.extend (Object.assign). JSON.stringify also wouldn't work any more with QUAIL getter/setter approach, which is particularly important since that would be the easiest way to store the data that comes out of these methods.