adding instructions for drag and drop to datalists

for #607 for #232 #421 #1
added test for remove from collection

for #470
added remove button to datalist directive for #470 #661
running jshint upon file changes in angular core
users usernames and ids are equivalent, but speaker's anonymouscodes and ids are equivalent

so overriding the id field of speakers to map to the anonymous code instead #1318 #487 #187
found bug in participants which is why they werent displaying anymore
adding more debugging if cant display a document in a corpus
tested remove in UI
clarifying instructions
not relying on add to unique non-exact matches of items in a collection