Merging Attributes [DRAFT]

This is currently a draft page to discuss the implementation about Merging attributes.

Required changes to get attribute mergering/demerging support:

1. Make capabilities aware of attributes
   1. Enhance capabilities XML Schema (XSD) to allow attributes in Schema
   2. make capabilities aware of supported content (kind of impossible?)
   3. Impossible(?) case: Multiple Telephone numbers different categories
   4. How to represent attributes content/values which are supported and which aren't supported? Special case are categories and multiple xmlfields.
2. Make osync_merger_demerge able to demerge attributes (not only xmlfields)
3. Make osync_merger_merger able to merge attributes (not only xmlfields)
4. Write a lot test cases...