TODO

LWM2M Features
--------------
  
 - LWM2M Security and LWM2M Server Objects:
 Implement these two objects in core as interfaces to lwm2m_server_t instances.
 Forbid clients to add objects with ID 0 or 1.
 * dnav WORKING ON IT *
 
 - Bootstrap interface:
 Implements LWM2M Bootstap Server as a special instance of lwm2m_server_t.
 
 - Access Control List
 
 - JSON support
  
 - Add token in every message
 
 - Handle Observe parameters
 
 - Keep-alive mechanism
 
 
 Implementation Improvments
 --------------------------
 
  - Store lwm2m_transaction_t per peer
  
  - bufferize all CoaP messages until all callbacks returned
  Currently if a server sends a request from its monitoring callback upon client
  registration, the client will receive the request before the ACK to its register
  and it will discard it.
  
  - Easy access to the lwm2m_context_t from objects callbacks
  
  - Allow object callbacks to return static buffers
  This can be done by a flag stating if the retruned buffer must be freed or not by the core.
  
  - Simplify lwm2m_uri_t handling
  Basically hide the flag member.
  
  - Use an unified result callback
  Add some parameter so that the same user callback can be used for all DM operations.
   
  - Use lwm2m-*-t types in er-coap-13
  To avoid multiple conversions.
  
  - Switch to void* parameters in lwm2m_list_* APIs
  
  - Change object interface to hide the whole TLV mechanism
  Useful when the core will support JSON.
  
  - Utility functions to easily implements objects
  The utility will just use read and write individual resources. Either statically or
  throught callbacks. See [https://github.com/01org/libdmclient]/tests/mgtobj/utils/static_mo_util.h