Add README and do some cleanup

* Add readme file. Content of the file comes mostly from
  http://projects.palaso.org/projects/chorus. Build instructions
  are updated.
* Remove files that are obsolete and also files that the
  buildupdate.*.sh script downloads.
Update README.md

Add instructions for UpdateDependencies.
Correct some grammar.
Merge pull request #4 from ermshiperete/readme

Add README and do some cleanup