persist bootstrap informations
Refactoring:

  * better API/impl isolation
  * better typing system, less opaque/TLV thrown at the user face
  * use the new typed nodes for writing
  * JSON API changed for following the new Java API
Lwm2mServer => LwM2mServer
moved TLV class to impl since it's no more part of the API
added some javadoc, fixed some equals/tostring
typo asyn => async
toString as string format
Rethrow exception thrown during the response visit
enhance project eclipsifiction of mvn eclipse:eclipse
fix some bugs.
use unix line delimiter (\n)
fix: call listeners when a client is updated
Functional & lambda friendly asynchronous API

Split old callback with multip method to functional interface
One consumer for reponse, one for exceptions.
avoiding NPE due to bad loading of xml files
use "org.eclipse.californium" instead of "ch.ethz.inf.vs.californium"
update osgi information (apache.felix).
Move definition of Californium repo to top level POM
Update property californium.version to 1.0.0-M1
Use managed version of californium-core
#35: Leshan WebUI should indicate Leshan version and/or Git SHA-1