Updated README

Hi,

attached patch updates README in CRIU repository:
- mark up text by markdown
- rename README file, because Github requires .MD
extension for files with Markdown inside
- describe the ways how to contribute to CRIU
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

README

-criu
-====
-
-An utility to checkpoint/restore tasks. Using this tool, you can
-freeze a running application (or part of it) and checkpoint it to
-a hard drive as a collection of files. You can then use the files
-to restore and run the application from the point it was frozen
-at. The distinctive feature of the CRIU project is that it is
-mainly implemented in user space.
-
-The project home is at http://criu.org
-
-Pages worth starting with are
-* Kernel configuration, compilation, etc: http://criu.org/Installation
-* A simple example of usage: http://criu.org/Simple_loop
-* More sophisticated example with graphical app: http://criu.org/VNC

README.md

+## CRIU (Checkpoint and Restore in Userspace)
+
+An utility to checkpoint/restore tasks. Using this tool, you can freeze a
+running application (or part of it) and checkpoint it to a hard drive as a
+collection of files. You can then use the files to restore and run the
+application from the point it was frozen at. The distinctive feature of the CRIU
+project is that it is mainly implemented in user space.
+
+The project home is at http://criu.org.
+
+Pages worth starting with are:
+- [Kernel configuration, compilation, etc](http://criu.org/Installation)
+- [A simple example of usage](http://criu.org/Simple_loop)
+- [More sophisticated example with graphical app](http://criu.org/VNC)
+
+### How to contribute
+
+* [How to submit patches](http://criu.org/How_to_submit_patches);
+* Send all bug reports to [mailing
+list](https://lists.openvz.org/mailman/listinfo/criu);
+* Spread the word about CRIU in [social networks](http://criu.org/Contacts);