Fix #575: Add sphinx dependency to dev-requirements.
- Added Sphinx to the dev_requirements.txt file.
- Changed Sphinx version to 1.2.3 to reflect latest version.
- Removed docs/requirements.txt from docs and travis.yml.
Fix #584 unicode string format error, 'string' to u'string'
Fix #583 Chinese Translation problem

Fixes #583.
Presently, the translation rates for Traditional Chinese and Simplified Chinese are 100%
Update to testing doc page from unittest to pytest

The contributor testing page contained examples of writing UnitTest
unit tests. The references and examples have been updated with pytest
information instead of UnitTest information. Therefore, new or existing,
contributors will now have a brief introduction to writing and running
the Freeseer pytest unit tests.

Fix #566
Related #420
Related #484