- fix for bug 2099: in language bindings task processing was stopped whenever a message was logged. I changed it so that it will only stop for CCopasiMessage::ERROR or  CCopasiMessage::EXCEPTION, but not for warnings or filtered messages
- issue 2100: improved handling of plots / reports. They can now be directly deleted from the dataModel (calling removeReportDefinition / removePlotSpecification). For reports, the deleted plot will also be removed from all tasks that used it before.