Bumped version for v0.9.1 release.

Bumped version for release.

Update __init__.py

We forgot to bump the version internally.

Xero is more strict on what gets sent back, add more ignore fields.

Make sure we're always dealing with unicode

Bump version number

Fixes ability to download PDFs by setting the accept header.

Get ready to roll 0.7.0-alpha1

Reworked setup.py to support wheels, and bumped version to 0.6.0