Markdown: add Markdown tool

For conversion of Markdown format to HTML.

From:

  http://daringfireball.net/projects/markdown/

License terms are easy to comply with (see doc/Markdown/License.text).
README: convert to Markdown format

Now we can easily generate an HTML version, while retaining readability
as a simple text file.
.gitignore: fixup VIM swapfile ignore
Add example from java showing legit satisfaction cycle
README: add more `code` formatting
Merge branch 'markdown'