Merge pull request #62 from oz123/develop

Fix for issue #61
Add @oz123 to contributors
bit of code refactoring
Merge branch 'develop' of github.com:areski/python-nvd3 into develop
Fix for issue #61

Improve LinePlusBarChart documentation
Add @oz123 to contributors
Add parameter extras
Add chart extras to template and add documentation
Add missing requirements

So that make build target works
 setuptools is redundant in requirements

 * If you distribute a file with setuptools (pip, virtualenv and so)
   It's OK to assume setuptools is pre-existing
Merge branch 'test_extras' into develop