use github flavoured markdown as default
Merge pull request #336 from orta/master

Use Github Flavoured Markdown as default markdown renderer
Removed superfluous removing of extension.

This causes problems since there is not supposed to be an extension anyway. Removing an extension from DTCoreText-1.2 causes the package name to be become DTCoreText-1.xar which is wrong.

Fixes #338
Add the .xar extension to the enclosure URL if necessary
Fixes #338

The extension xar is added to the output file path for the docset utility, but it is not checked that it is in the url. Without this there is a scenario where the URL is missing the extension.
Merge pull request #339 from Cocoanetics/atomurlfix

Fixes a bug causing the xar-file URL to be incorrect
Merge branch 'master' of https://github.com/tomaz/appledoc
Merge branch 'master' of https://github.com/tomaz/appledoc