Update SimpleAnnotationServerV2Adapter.js

[rchavez-neu]

Using SimpleAnnotationServerV2Adapter.js with Mirador 3.1.1. and mirador-annotation plugin 0.5.0, it appears that the V3 annotation structure has changed slightly. This causes line 80 (full: v3anno.target.source.id) of SimpleAnnotationServerV2Adapter.js not to fucntion properly -- the "full" JSON key will not have a canvadIS URI value.

changing line 80: full: v3anno.target.source.id to: full: v3anno.target.source

fixes the issue and enables SimpleAnnotationServerV2Adapter.js to output the correct canvasID s