Add method to check if empty collections should be included in result serialized json result
Update documentation
Update descriptor's with Fields()/Path()
Update mappings to allow inheritance for multifieldmap
Add multifieldmap also the GenericMapping
Change mapping to use contructor for default type
Fix full mapping test

If store and enable are the same values as the server are configured as
the items are not returned back as response when get-mapping are
executed.
Merge pull request #885 from Tasteful/issue/873

Use MultiFieldMapper as base for the core-mappers