#87 enable osgi for artifacts.
use import package with version range for slf4j as jsonld-core's dependencies are already bundle.
Note : if you use java security in your osgi stack, you need to add this 2 permissions to get the lib working :
(java.lang.RuntimePermission accessDeclaredMembers)
(java.lang.reflect.ReflectPermission suppressAccessChecks)
Disable RDF2GO again, need to remove the Aduna repository from the RDF2GO pom files before reenabling it
Add OSGi note to readme, fixes #87

also bump sesame to 2.7.13
Merge branch 'florent-andre-master'