Merge pull request #6746 from ritzalam/improve-logging

...b/src/main/java/org/bigbluebutton/api/MeetingService.java

...bluebutton/presentation/DocumentConversionServiceImp.java

...bigbluebutton/presentation/imp/Jpeg2SwfPageConverter.java

...gbluebutton/presentation/imp/Office2PdfPageConverter.java

...gbluebutton/presentation/imp/OfficeDocumentValidator.java

...bluebutton/presentation/imp/OfficeDocumentValidator2.java

...button/presentation/imp/OfficeToPdfConversionService.java

.../bigbluebutton/presentation/imp/Pdf2SwfPageConverter.java

...ton/presentation/imp/PdfToSwfSlidesGenerationService.java

.../bigbluebutton/presentation/imp/Png2SwfPageConverter.java

...ava/org/bigbluebutton/presentation/imp/PngCreatorImp.java

...rg/bigbluebutton/presentation/imp/SvgImageCreatorImp.java

...rg/bigbluebutton/presentation/imp/TextFileCreatorImp.java

...g/bigbluebutton/presentation/imp/ThumbnailCreatorImp.java

bigbluebutton-web/grails-app/conf/logback.xml

...rs/org/bigbluebutton/web/controllers/ApiController.groovy