Add the ability to get a band's index in its dataset
Get a band's dataset
Identify a driver given a source name
Move to bigarrays for most data exchange; Geotransform cleanups
Bands now carry their native data types with them

This is to prepare for block IO support which always utilizes a block's
native data type.
Add block IO support
Allow reuse of bigarrays for block reads
Version bump
Add functions for iterating over blocks in a band