refactor the README to markdown flavore

refinement and refactor of the README file:
(1) rewrite it in Markdown and use Python highlight for the source code
(2) add some information about KGTP to make the document more clear
ignore the compiled files, tmp files and other trivial stuff
Merge pull request #25 from hustcalm/master

refactor the README to markdown flavore
Thanks work of Lihang Li <licalmer@gmail.com>.