OpenSeaDragonViewer: multiple instances of annotations

[bwbohl]

When showing and hiding annotations in OpenSearagonViewer multiple times, each time, the annotations are added to the view (but not deleted on hide, as in ImageViewer). This results in multiple instances of each annotation being displayed and consequently a failure of annotation previews and opening the annotation.

Apparently, this is due to the corresponding function being empty:

Edirom-Online/app/view/window/image/OpenSeaDragonViewer.js

Lines 126 to 128 in 78d4d32

	removeShapes: function() {
	},

For testing:

1. go to https://klarinettenquintett.weber-gesamtausgabe.de/
2. open "Autograph A" from the navigator
3. go to page 2
4. In Menu "Anmerkungen" select "Anmerkungen ein-/ausblenden"
5. check how the interface works
6. repeat step 4 ad libidum
7. see how the number of annotation icons duplicates
8. try the interface

This is a critical bug!

[bwbohl]

@hizclick & @daniel-jettka this might be a good first issue ;-)

[bwbohl]

closed with 98f15db