Working version for Django v2.2

[pirate]

Made a few simple changes to get it working in modern Django version. Unfortunately, it's not perfect, but at least it runs now.

I noted the new limitations in the readme:

Note, you must run Django with threading disabled in order for statprof to work!

  $ ./manage runserver --noreload --nothreading

You may experience issues with staticfiles loading in chrome when `--nothreading` is passed.

This is because chrome opens two initial connections, which blocks when Django is only able to respond to one of them.  To fix this, you must serve staticfiles via separate staticfile server, such as nginx with a reverse_proxy to your Django runserver.

[pirate]

@atereshkin I know you're probably busy / not using this library anymore, if you don't feel like merging this because then you'll have to continue to support it, you're welcome to archive the repo on github and point people to my fork instead, I don't mind maintaining it.

Otherwise you're welcome to merge this, it fixes most of the outstanding issues and works out of the box with Django v2.2.

[shayneoneill]

@pirate Any chance on an update of your fork to get it working on more up to date djangos?