Update version and travis config

We're using a token in the project settings.

Update AUTHORS.txt

Update change log

Update __init__.py

Add code of conduct

Update version, change log, authors

Use post-release tag.

Restor __rmul__ with an explanation

Update change log and version

Merge pull request rasterio#23 from sgillies/strictly-degenerate

Make is_degenerate exact, not approximate