Fixed integration with custom classloaders
Internal classes used for the purpose of integrations are now loaded on the classloader where the integration is applied. This allows for support of applications running with non-standard classloaders such as Spring Boot's executable jar classloader.
Logging has been changed to use an internal SLF4J implementation that is scoped to just dd-java-agent. The result is agent logs are piped to STDERR. This fixes the lack of logging for executable Spring Boot jars. Configure the log level with the following property -Ddd.slf4j.simpleLogger.defaultLogLevel=debug.