Marked's gfm for tables is too strict

[3rd-Eden]

If we render grunt-notify you can see that the github tables are severely broken:

While github shows them correctly. https://github.com/dylang/grunt-notify

[3rd-Eden]

The problem is that the whole page is rendered as HTML.

[3rd-Eden]

Reported as markedjs/marked#381