PmBeanBase.Nested: Protected against mis-usage. Setting a bean is not
allowed in embedded state.
PmTable: Moved reaction on PM parent value changes to a method that can
be overridden by domain developers.
Attribute value converter:
- fixed a problem in PmConverterOptionBased. (Wrong start object was
used for ID expression.)
- undone deprecation of convertBacking..value methods.
  These methods are very useful to be able to write simple code.