Added generic controller for task popovers

app/Template/task_popover/change_assignee.php

@@ -0,0 +1,20 @@
+<section id="main">
+    <div class="page-header">
+        <h2><?= t('Change assignee for the task "%s"', $values['title']) ?></h2>
+    </div>
+    <form class="popover-form" method="post" action="<?= $this->url->href('TaskPopover', 'updateAssignee', array('task_id' => $values['id'], 'project_id' => $project['id'])) ?>">
+
+        <?= $this->form->csrf() ?>
+
+        <?= $this->form->hidden('id', $values) ?>
+        <?= $this->form->hidden('project_id', $values) ?>
+
+        <?= $this->task->selectAssignee($users_list, $values, array(), array('autofocus')) ?>
+
+        <div class="form-actions">
+            <button type="submit" class="btn btn-blue"><?= t('Save') ?></button>
+            <?= t('or') ?>
+            <?= $this->url->link(t('cancel'), 'board', 'show', array('project_id' => $project['id']), false, 'close-popover') ?>
+        </div>
+    </form>
+</section>