Tendenci

**Improvements**

* Video thumbnails will be pulled from youtube API for youtube videos if needed (when embedly is not available), so no need to upload thumbnails for youtube videos.
* Updated version for the dependencies django-simple-captcha (to 0.5.5) and Pillow (to 4.2.1).
* Added categories to the admin backend.

**Fixes**

* Fixed the members graph on dashboard
* Removed the extra space from CAPTCHA image.

**Improvements**

* A new site setting is added for embed.ly API key to allow your site to sign up for your own embed.ly API Key.
* Made video categories draggable.
* Handled html emails for Helpdesk tickets - stripped html from email body and added to ticket description.

**Fixes**

* Fixed raw HTML showing up in renewal alert.
* Removed the deprecated sets module.
* Fixed UnicodeDecodeError on jobs add_message.
* Disabled the correct button during event registration
* Updated the way of handling unsubscribe url to prevent it from being broken.

* Upgraded tinymce from 4.3.8 to 4.6.3 which fixed the issue about image linking not working.
* Made the number of members on profiles consists with the one on memberships reports.

* Bugfix and updated for email edit
* Moved "generated by Tendenci" email footer to a template include.
* Payment/Invoice bugfixes

* Bugfix AttributeError
* Allow user to view/edit invoice if bill_to_email matches
* Include guid in Pay Online button on Invoices
* Removed deprecated PayPal redirect_cmd parameter

- Support Django 1.8