Fix for UTF-8 formatted datapackage.json files

The .decode() call was throwing errors on UTF8 files with accented characters. 

I found that removing it had no issues with importing, and fixed the bug. I've tested with the example CSV on the README file and it appears to work as expected.
Merge pull request #27 from rlafuente/patch-1

Fix for UTF-8 formatted datapackage.json files