Remove useless class

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>
Extract the NOT MANAGED constant

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>
Update slf4j package version

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>
Also export the org.ow2.chameleon.core.activators package to let the directory monitor to be reused.

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>