moving wheel dependency to setup.py, making requirements.txt the source for the code dependencies
added requirements-build.txt, cleanup setup.py code
using nose.collector as test suite
Merge pull request #7 from scrapinghub/fixing-packaging-issues

Fixing build and packaging issues
proposing easy to use API
Merge pull request #13 from eliasdorneles/offering-easier-api

Proposing easy to use API
Merge branch 'master' into chinese-support