Added the column extractR with corrections

[saxenism]

In response to the review of my PR here, I have opened this PR from an alternative branch of my forked repository(not the master).

1. All the mentioned failed test cases are now passing and thus have been added to the tests file.
2. Code Styling has been paid special attention to.
3. Mentioned changes were made to the vignette.
4. Iterators were not initialized.
5. Functions were made efficient and all return statements were removed.

Thanks!