Acceptance criteria:

• automatic/default conversion support: JCR values should be effortlessly convertible to the expected field/column definition types (via BeanUtils converter functionality).
• untie PropertySet implementation from field/column definition - instead a dry and simple property definition should be used: id and type should be enough.
• get rid of the alternative JcrPropertySet implementation: there are currently two of them, only JcrNodePropertySet needs to remain.
• fix the synchronisation issues between the Grid and the JcrNodePropertySet: not necessarily the issue of a property set component itself
• support for editing JCR properties.
  • generalise relevant components so that properties can be displayed and edited in the Grid/TreeGrid.
  • split JcrItemPropertySet functionality-wise (provide implementation for the Nodes and Properties separately).
  • introduce an interface (and impl) for the renamable properties.