Updates on multichannel write

src/tmltranslator/TMLChannel.java

src/tmltranslator/TMLMapping.java

src/tmltranslator/TMLMappingTextSpecification.java

src/tmltranslator/touppaal/TML2UPPAAL.java

src/ui/GTMLModeling.java

src/ui/tmldd/TMLArchiCommunicationArtifact.java

src/ui/window/JDialogCommunicationArtifact.java