oBIX object serialization based on EXI

```
Currently oBIX objects are serialized to XML and then to EXI and the same way 
around for deserialization. An oBIX encoder/decoder for EXI should be provided 
that allows to directly serialize oBIX objects to EXI.

```

Original issue reported on code.google.com by `markus.j...@gmail.com` on 7 Mar 2013 at 8:37
