Merge pull request #3616 from riadvice/detect-heavy-to-convert-pptx

...on/core/pubsub/receivers/PresentationMessageListener.java

bigbluebutton-client/locale/en_US/bbbResources.properties

...utton-client/src/org/bigbluebutton/core/EventConstants.as

...client/src/org/bigbluebutton/main/api/ExternalApiCalls.as

.../org/bigbluebutton/main/api/maps/ExternalApiEventMap.mxml

...on/modules/present/events/OfficeDocConvertInvalidEvent.as

...c/org/bigbluebutton/modules/present/services/Constants.as

...ton/modules/present/services/messaging/MessageReceiver.as

...bluebutton/modules/present/ui/views/FileUploadWindow.mxml

bigbluebutton-web/build.gradle

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

...igbluebutton/presentation/ConversionMessageConstants.java

...bluebutton/presentation/DocumentConversionServiceImp.java

...tton/presentation/OfficeToPdfConversionSuccessFilter.java

.../org/bigbluebutton/presentation/UploadedPresentation.java

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

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