Loggers should be declared non-static

[ViToni]

Loggers are declared as private static final. This can have impact when having the library deployed on "shared" classpaths.
It is prefereable to have them non-static.
If you care about serialization Loggers could be changed to be also transient.

For reference see:
http://slf4j.org/faq.html#declared_static
https://cwiki.apache.org/confluence/display/COMMONS/Logging+StaticLog

Projects implementing such a policy:
https://www.eclipse.org/smarthome/documentation/development/guidelines.html#e-logging
https://www.openhab.org/docs/developer/guidelines.html#f-logging

(Have to admit these projetcs are closely related but both are supposed to support dynamic reloading of JARs/ bundles.)

[marci4]

@ViToni thx for pointing this out.
We do not plan serialize the logger.

Pull request welcome!

[ViToni]

Created PR #970.