Make events user creatable.

Wording and imagery is subject to change (obviously).

Just wanted to get this reviewed so that when the wording's decided it's easy to pull the trigger.

:eyeglasses: @umbrae @Deimos 
This is only supported by IE10+, and I'm not sure how IE9 will break in this situation. It may make a transparent button if it has no background and the bgcolor is set to transparent. Can you set transparent to be a color?