Using the simplifiedAutoLink option does not return the expected GFM behaviour when parsing links without a http prefix.
Previously, `www.google.com` would be parsed into `<a href="www.google.com">www.google.com</a>`.
With this fix, showdown behaves like GFM, and the result is `<a href="http://www.google.com">www.google.com</a>`
Closes#284, closes#285
Github Flavored Markdown supports a specific table syntax. Table support was already available as an extension.
With this commit, the feature was moved to core, adding this feature to showdown through an option called "tables".
Related to #164
