RF: refactor MINC1 tests ready for MINC2
NF: add deprecated.py module with tests

Add helpers for deprecating modules and classes
RF: move minc module to minc1 name and deprecate

Move minc.py to minc1.py and add deprecation shells for old imports.
NF: First pass at MINC2 loading with tests

Add MINC2 loading - very basic, with no save.
Inherit MINC1 tests
Add example file and check loaded parameters against mincstats
DOC: expand docstring for MINC2
NF: add MINC2 to standard imports

Add Minc2Image to top-level namespace.
TST: add MINC2 to image API tests
BF: fix error for negative zooms

MINC files can have negative zooms, which SpatialImage does not allow.
Merge pull request #190 from matthew-brett/minc2-support

MRG: first draft of MINC2 support

Very basic support for loading MINC2 images (as basic as support for MINC1).

Refactoring of MINC1 to make this easier.