asciidoc related enhancements

Hello,

i made some changes to your code. You might like it.

*   jbake now does not treat all types other then page as post. The reason ist that normally it is fine to have the same template for all posts. But for pages you might define a different type and thus a different template.

*   Set asciidoc renderer to unsafe and the base dir to jbake root.

Cheers,
Vadim