A few doc clean up tasks.

1. Delete the now redundant doc directory.
2. Add a new directory examples to hold app example documents.
3. Add a document for English POS Tagger in examples.
4. Update Getting Started to point to correct POS Tagger doc.
5. Update/fix the doc configuration yml.
Merge pull request #24 from dmsurti/docs-cleanup

A few doc clean up tasks.