This disables highlighting for fenced code blocks without explicitly specified language. It also introduces a new `PygmentsCodeFencesGuessSyntax` config option (defaulting to false).
To enable syntax guessing again, add the following to your config file: `PygmentsCodeFencesGuessSyntax = true`
This is a breaking change.
This commit adds a new PygmentsCodeFences config option (default false), which if true will allow GitHub style backtick code fences around code, which will then be rendered by Pygments.
For example:
``` language
your code
```
can be used instead of {{< highlight language >}}your code {{< /highlight >}}.
Fixes#362
