Update logging statements in ServicePool to not use string concatenation.
Update to use the SLF4J 1.7.x's exception logging mechanism.
Call .toString() instead of .getMessage() in exception logging.
Call .toString() instead of .getMessage() in exception logging.
Call .toString() instead of .getMessage() in exception logging.
Merge pull request #141 from bbeck/logging

Update logging statements in ServicePool to not use string concatenation...