Rewrite of emfjson for version 0.9.0

major changes:
- maven based project
- simplify code base
- create core project sharing common functionalities used by emfjson-jackson and emfjson-gwt
- improve performance by using jackson streaming api and caching
Update support for UUIDs
Update GWT tests
Rename JsResource and Factory to JsonResource
Add p2-build
unwanted
Better exception handling.
Add HttpHandler.create to handle creation of resources via POST method.
Merge branch 'maven-first-build'
Fix pom files.