- add number of responders on poll result

akka-bbb-apps/build.sbt

...ain/scala/org/bigbluebutton/core/MessageSenderActor.scala

...pps/src/main/scala/org/bigbluebutton/core/apps/Poll.scala

.../src/main/scala/org/bigbluebutton/core/apps/PollApp.scala

akka-bbb-fsesl/build.sbt

bbb-common-message/build.sbt

.../bigbluebutton/common/messages/PollShowResultMessage.java

...src/main/java/org/bigbluebutton/common/messages/Util.java

bigbluebutton-apps/build.gradle