Add AffineMatrix class. See #80.
First take on a pad() function.

See #84.
Make xoff and yoff aliases for c and f.

Also derived AffineMatrix from an anonymous namedtuple!
All public functions now use AffineMatrix.

Proposing this as the solution to #80.
Implement the windows method suggested in #78.
Switch to affine.Affine.
Add affine requirement.
Finish switching to affine.Affine.
Test the window() method.
Make affine>=1.0 a requirement.
Fix busted config file.
Update README post-Affine.
Better support for existing applications.

A deprecation warning is raised from the transform property and
an affine property is added to provide the new feature.

For method and function arguments, we sniff out GDAL geotransforms
and try to do the right thing with them, also raising deprecation
warnings in these cases.
Wrapping up work toward #86.

All tests pass, all examples are working.

TODO: docs.
Update readme and datasets doc.
Nonstandard repo shouldn't be needed now.

Towards a fix of #88.
Install dependencies with -y

Towards a fix of #88.
Add the ubuntugis ppa back in.
Add repo with -y
Stub for section on writing data.