Fix README.md typos

- Since the project is hosted both on GitHub and BitBucket, I
  removed the links to other project's files, so no cross-
  linking between GitHub and BitBucket repos will happen
  anymore.

- Fixed the `fork` link. It was pointing to a wrong link. Now
  it correctly points to the right target on both the repos.
Fix README.md for repos

Since the repo is hosted on GitHub and mirrored on BitBucket, the
instructions into README.md file have been changed in order to
not refer to a particular link inside the repo. This prevents the
building of wrong cross-links between the host and mirror repo.
Merge pull request #3 from Ragnarokkr/fix-readme-for-repos

Fix readme for repos