MessageProcessingSample
Revert "MessageProcessingSample"

This reverts commit 4daeb4c1052c53fa62c27f0fa36c770616e87165.
Updates to Message Layer sample
Updates to SymbolDictionarySearch sample for Store. Adds Clear Category and Clear Map buttons.
Add Progress Bar to DynamicLayerAddData
Updated LoadWebMapMVVM to use ListBox so selected web map is shown as selected in the list.
Fixes as per feedback from Antti.
Reworked try/catch for taskcanceledexception.
Remove unused line of code
Removed wait on SpatialReferenceChanged. Just do wait on LayersLoaded to ensure the MessageLayer has been loaded before populating it with the messages.
Removed wait on SpatialReferenceChanged. Just wait on LayersLoaded.
Store version with same updates as Desktop.
Merge pull request #38 from Esri/kdalton/SampleFeedback

Kdalton/sample feedback