Merge pull request #183 from matthew-brett/py3-standard-exceptons

RF: continue py3 update standarizing exceptions

We were using sys.exc_info to work around Python 2.5 / 3 compatibility; use the
new exception syntax, now we depend on Python 2.6
Merge pull request #184 from matthew-brett/win-longdouble-fixes

BF: deal with some oddness in windows longdouble

An old installation of python x, y revealed that it's possible for windows
longdouble to change after initial import; work round this with a small hack.

Stop longdouble high integer precision check if longdouble does not have high integer precision.

Fix a windows doctest failure.
Merge pull request #181 from matthew-brett/file-slicing

MRG: implement slicing directly on images on disk

These commits implement a relatively optimized way of getting a slice of an
array that is not lyet loaded into memory, but is still on disk.

The obvious use is to allow slicing of e.g. nifti images that have not yet been
loaded. For example, it is reasonably fast to load one or several volumes
(slicing on the last dimension) using these routines.
BF: work round int casting bug in numpy 1.4.1

Innocently using int(val) on a uint64 type caused a nasty error that I'd
previously caught in a different context in ``as_int()`` above.  Put in
same fix.
BF: byteswap data before checking hash of buffer

Hash depends on endianness of the data in memory; swap to little-endian
before checking hash.
Merge pull request #187 from matthew-brett/img-properties-api

MRG: make data, affine, header properties, test API

Add:

* img.header - prefer to img.get_header()
* img.affine - prefer to img.get_affine()
* img.dataobj - direct access to old img._data

Add tests of image API so that someone implementing a new image type can
test whether they conform to the API.

Use the API tests to check the new properties.
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