DOC: Fix formula import convention.
DOC: Fix broken link
Merge pull request #1514 from jseabold/fix-formula-import

DOC: Fix formula import convention.
Merge pull request #1515 from jseabold/fix-docs-link

DOC: Fix broken link
DOC: Be clear about data attribute of Datasets
Merge pull request #1517 from jseabold/datasets-docs

DOC: Be clear about data attribute of Datasets
DOC: Update examples contributing docs for current practice.
Merge pull request #1516 from jseabold/uploading-examples

DOC: Update examples contributing docs for current practice.
DOC: Ask for release notes and example.
Merge pull request #1518 from jseabold/contributing-docs

DOC: Ask for release notes and example.
CLN: Refactored so that there is no longer a need for 2to3

The codebase has been refactored so that it can exist in a single, unified base.
The strategy closely followed six and pandas.compat, but does not involve any further
dependencies.

The compatability location has been renamed form compatnp, which housed compatnp.py3k, to
just compat, and the main py3k compatability files are in __init__.py so that they can
be directly accessed