md: Fix marked link in README
md: Update marked and use minified version
md: Autofocus and select input text on load
md: CSS improvements

* Style tables
* Add border to pre blocks
md: Option to show the generated HTML source
md: Enable "Surround HTML body" by default
md: Put some examples Markdown examples in the default text
md: Add newline after "body" html prefix
md: Syntax highlighting
md: Change order of controls in the panel
md: Slightly change <a> style
md: Fix broken HTML preview on refresh
md: Option to export CSS styles too
md: Bigger font size for exported styles