feat(browser): Emit a browser error when a disconnect occurs.

Show the suite as failing when using the karma plugin for intellij; prior
behavior was, even though the remainder of the suite would be skipped, intellij
still showed it as passing.

lib/browser.js

@@ -37,6 +37,7 @@ var Browser = function (id, fullName, /* capturedBrowsers */ collection, emitter
     self.state = DISCONNECTED
     self.disconnectsCount++
     log.warn('Disconnected (%d times)' + (reason || ''), self.disconnectsCount)
+    emitter.emit('browser_error', self, 'Disconnected' + reason)
     collection.remove(self)
   }
 

test/unit/browser.spec.js

@@ -394,9 +394,13 @@ describe('Browser', () => {
       socket.emit('result', {success: true, suite: [], log: []})
       socket.emit('disconnect', 'socket.io reason')
 
+      var spyBrowserError = sinon.spy()
+      emitter.on('browser_error', spyBrowserError)
+
       timer.wind(10)
       expect(browser.lastResult.disconnected).to.equal(true)
       expect(spy).to.have.been.calledWith(browser)
+      expect(spyBrowserError).to.have.been.called
     })
 
     it('restarting a disconnected browser', () => {