Using `pedantic: true` breaks GFM

[MPvHarmelen]

According to the documentation of the pedantic option of marked:

If true, conform to the original markdown.pl as much as possible. Don't fix original markdown bugs or behaviour. Turns off and overrides gfm.

https://github.com/gnab/remark/blob/b658a0c61434e4fe1ccec75ef254f4a78a13ebef/src/remark/converter.js#L13

[yuekai]

Changing pedantic: true to false passes all tests.