Set TinyMCE editor width/height

Ghost User
2017-06-28T19:54:41+02:00

Closes #386

#### Previous behaviour
Steps to reproduce:

1. Go to event edit page
2. HTML editor is really small

#### New behaviour
Steps to validate that it works:

1. Go to event edit page
2. HTML editor is large enough to easily ed...

Closes #386 (closed)

Previous behaviour

Steps to reproduce:

1. Go to event edit page

2. HTML editor is really small

New behaviour

Steps to validate that it works:

1. Go to event edit page

2. HTML editor is large enough to easily edit text