Refactors MessageHandler.send to remove callbacks
Refactors GetAnnotationsRequest and GetPageRequest
Refactor the CSS rules for the overlayContainer
Merge pull request #4777 from Snuffleupagus/overlay-refactor

Refactor the CSS rules for the overlayContainer
Merge pull request #4752 from yurydelendik/refmsghdlr

Refactors MessageHandler.send to remove callbacks