Merge Client Wrapper logs with S2OPC logs
The log system of the client wrapper, libsub, and PyS2OPC, is independent from the log system of S2OPC. This is caused by the libsub, which was expected to output logs through a callback, so that logs could be merged with other log systems.
However, it would be good to have a common log facility that would comply to such requirement (see #762 (closed), #545 (closed)). This also would ease log when there is no file system (see #601 (closed)).
Merging log systems would also allow for LOG_LEVEL_...
filtering that is not yet provided by the client wrapper log facility.
Edited by Pierre-Antoine BRAMERET