reset auth forms on app reset

Introduces 'resettable' directive which runs at super high priority
and listens for the '$reset' event on the scope upon which the
element is stored to its pristine condition via a full element
transclude.

closes #159

h/js/controllers.coffee

 class App
   scope:
+    username: null
+    email: null
+    password: null
+    code: null
     sheet:
       collapsed: true
       tab: 'login'
@@ -15,8 +19,6 @@ class App
     $compile, $element, $http, $location, $scope,
     annotator, flash, threading
   ) ->
-    $scope.reset = => angular.extend $scope, @scope
-
     {plugins, provider} = annotator
     heatmap = annotator.plugins.Heatmap
     heatmap.element.appendTo $element
@@ -159,7 +161,7 @@ class App
         $http.post 'logout', '',
           withCredentials: true
         .success (data) =>
-          $scope.reset()
+          $scope.$broadcast '$reset'
           if data.model? then angular.extend($scope, data.model)
           if data.flash? then flash q, msgs for q, msgs of data.flash
 
@@ -185,6 +187,8 @@ class App
         collapsed: !show
         tab: 'login'
 
+    $scope.$on '$reset', => angular.extend $scope, @scope
+
     # Fetch the initial model from the server
     $http.get '',
       withCredentials: true
@@ -192,7 +196,7 @@ class App
       if data.model? then angular.extend $scope, data.model
       if data.flash? then flash q, msgs for q, msgs of data.flash
 
-    $scope.$evalAsync 'reset()'
+    $scope.$broadcast '$reset'
 
 
 class Annotation

h/js/directives.coffee

@@ -71,6 +71,21 @@ recursive = ['$compile', '$timeout', ($compile, $timeout) ->
 ]
 
 
+resettable = ->
+  compile: (tElement, tAttrs, transclude) ->
+    post: (scope, iElement, iAttrs) ->
+      reset = ->
+        transclude scope, (el) ->
+          iElement.replaceWith el
+          iElement = el
+          iElement[0].$reset = reset
+      reset()
+      scope.$on '$reset', reset
+  priority: 5000
+  restrict: 'A'
+  transclude: 'element'
+
+
 tabReveal = ['$parse', ($parse) ->
   compile: (tElement, tAttrs, transclude) ->
     panes = []
@@ -125,5 +140,6 @@ thread = ->
 angular.module('h.directives', ['ngSanitize'])
   .directive('annotation', annotation)
   .directive('recursive', recursive)
+  .directive('resettable', resettable)
   .directive('tabReveal', tabReveal)
   .directive('thread', thread)