Merge branch 'adding-accessibility-changes'

...luebutton/modules/present/business/PresentationService.as

...t/src/org/bigbluebutton/modules/present/managers/Slide.as

bigbluebutton-web/.gitignore

bigbluebutton-web/grails-app/conf/UrlMappings.groovy

bigbluebutton-web/grails-app/conf/spring/doc-conversion.xml

...gbluebutton/web/controllers/PresentationController.groovy

...org/bigbluebutton/web/services/PresentationService.groovy

...igbluebutton/presentation/ConversionMessageConstants.java

.../java/org/bigbluebutton/presentation/TextFileCreator.java

...n/presentation/imp/ImageToSwfSlidesGenerationService.java

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

...presentation/imp/SwfSlidesGenerationProgressNotifier.java

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

...org/bigbluebutton/api/messaging/NullMessagingService.java