Adjustments to support presentation pods in 2.1

...sentation-pods/server/handlers/syncGetPresentationPods.js

.../presentation-pods/server/modifiers/addPresentationPod.js

bigbluebutton-html5/imports/api/presentations/index.js

...n-html5/imports/api/presentations/server/eventHandlers.js

...ts/api/presentations/server/handlers/presentationAdded.js

...s/api/presentations/server/handlers/presentationChange.js

...entations/server/handlers/presentationConversionUpdate.js

...i/presentations/server/handlers/presentationCurrentSet.js

...pi/presentations/server/handlers/presentationInfoReply.js

...s/api/presentations/server/handlers/presentationRemove.js

...rts/api/presentations/server/modifiers/addPresentation.js

.../api/presentations/server/modifiers/removePresentation.js

.../presentations/server/modifiers/setCurrentPresentation.js

...n-html5/imports/api/slides/server/handlers/slideChange.js

...ton-html5/imports/api/slides/server/modifiers/addSlide.js

...imports/api/slides/server/modifiers/changeCurrentSlide.js

...-html5/imports/api/slides/server/modifiers/resizeSlide.js