Add missing titles to SRP buttons (#654)

Add pending request counter.
Restrict SRP status to choices.

Closes #643

srp/migrations/0002_srpuserrequest_srp_status_choices.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.5 on 2017-01-18 20:21
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('srp', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='srpuserrequest',
+            name='srp_status',
+            field=models.CharField(choices=[('Pending', 'Pending'), ('Approved', 'Approved'), ('Rejected', 'Rejected')], default='Pending', max_length=8),
+        ),
+    ]