Update README

README file name changed to README.md to be able to use markdown syntax,
replaced <code> tags with markdown code Inline formats and Multiple
lines code formating where needed, links updated: link
http://www.mumbles-project.org/ does no longer works as well as
http://det.cable.nu/teatime/index.rbx?r=2.8.0
so they where replaced to https://github.com/xiongchiamiov/mumbles and
http://www.t2-project.org/packages/teatime.html respectively. Add Emacs
tested version item 24.4. Replaced titles like = title = to markdown
titles.

https://help.github.com/articles/markdown-basics/