finishing abstract works branch

[eroux]

I don't really understand why we didn't finish that, but there are still many properties that are incorrectly named, for instance:

• workPartType (and all it individual values) -> instancePartType
• workPartOf -> instancePartOf (and partIndex, parttreeindex, etc.)
• WorkLocation (and associated) -> (Instance)Location
• VolumeImageAsset -> ImageGroup
• itemVolumes -> instanceNbVolumes (or something like that)
  etc.

this it top priority