Update and standardise QA implementations

- ES6ify (now using class syntax to define QAItem objects)
- Fix bug with KeepRight marker rendering not updating properly
- Use `qa-` prefix for the UI element classes to differentiate from iD
validation error related UI element classes
- Move away from "error" where possible in source
- Move away from snake_case naming where possible

Note that some function/method names have been untouched to make life
easier for v3 development. Have added note comments where appropriate.

modules/behavior/hover.js

@@ -5,7 +5,7 @@ import {
     select as d3_select
 } from 'd3-selection';
 
-import { osmEntity, osmNote, qaError } from '../osm';
+import { osmEntity, osmNote, QAItem } from '../osm';
 import { utilKeybinding, utilRebind } from '../util';
 
 /*
@@ -131,9 +131,9 @@ export function behaviorHover(context) {
                 entity = datum;
                 selector = '.data' + datum.__featurehash__;
 
-            } else if (datum instanceof qaError) {
+            } else if (datum instanceof QAItem) {
                 entity = datum;
-                selector = '.' + datum.service + '.error_id-' + datum.id;
+                selector = '.' + datum.service + '.itemId-' + datum.id;
 
             } else if (datum instanceof osmNote) {
                 entity = datum;