added IssueManager

- IssueManager performs validation on the current graph and also
   stores the issues and notifies listeners when the issues changed

modules/core/context.js

@@ -13,6 +13,7 @@ import { select as d3_select } from 'd3-selection';
 import { t, currentLocale, addTranslation, setLocale } from '../util/locale';
 
 import { coreHistory } from './history';
+import { IssueManager } from '../validations/issueManager';
 import { dataLocales, dataEn } from '../../data';
 import { geoRawMercator } from '../geo/raw_mercator';
 import { modeSelect } from '../modes/select';
@@ -95,10 +96,10 @@ export function coreContext() {
 
 
     /* Straight accessors. Avoid using these if you can. */
-    var connection, history;
+    var connection, history, issueManager;
     context.connection = function() { return connection; };
     context.history = function() { return history; };
-
+    context.issueManager = function() { return issueManager; };
 
     /* Connection */
     context.preauth = function(options) {
@@ -446,6 +447,8 @@ export function coreContext() {
     context.changes = history.changes;
     context.intersects = history.intersects;
 
+    issueManager = IssueManager(context);
+
     // Debounce save, since it's a synchronous localStorage write,
     // and history changes can happen frequently (e.g. when dragging).
     context.debouncedSave = _debounce(context.save, 350);

modules/ui/commit_warnings.js

@@ -11,8 +11,8 @@ export function uiCommitWarnings(context) {
 
     function commitWarnings(selection) {
 
-        var changes = context.history().changes();
-        var validations = context.history().validate(changes);
+        // maybe call these issues now?
+        var validations = context.issueManager().validate();
 
         validations = _reduce(validations, function(validations, val) {
             var severity = val.severity;

modules/validations/issueManager.js

@@ -0,0 +1,22 @@
+import * as d3 from 'd3';
+import { utilRebind } from '../util/rebind';
+
+export function IssueManager(context) {
+    var dispatch = d3.dispatch('reload'),
+        self = {},
+        issues = [];
+
+    self.getIssues = function() {
+        self.validate();
+        return issues;
+    };
+
+    self.validate = function() {
+        var changes = context.history().changes();
+        issues = context.history().validate(changes);
+        dispatch.call('reload', self, issues);
+        return issues;
+    };
+
+    return utilRebind(self, dispatch, 'on');
+}