RF: refactor installation checks to check scripts

Rewrite of testers module for clarity, in part.  Add a routine that
allows us to check if any scripts have been missed in the installation.
Add this to the Makefile as a target and to the release checklist.
DOC: add/expand docstrings, move code for testers
RF: add informative message when check-files is OK

Also return something that could be used as an error code.
BF: make compatible with pydicom 0.9.7

Pydicom 0.9.7 returns some fields as Python Decimals, when previously
they were floats.  This causes a mess when using values in an array,
because the array becomes objects rather than floats, and, well, it
doesn't go well.  Tests pass for me with pydicom 0.9.5 through 0.9.7
with these changes.
Merge pull request #126 from yarikoptic/master

point to nipy organization's nibabel instead of the original Michael's for issues and changes
RF: use map instead of list comprehensions

map looks a little nices here; from suggestion by Alexandre Gramfort
RF: refactor, rename nifti diagnostic script

Script didn't have any usage, help, etc.  Stolen from nib-ls.  Renamed
to nib-nifti-dx to fit with our new naming scheme.
BF: add missing scripts to setup.py

We were missing the dicomfs and nifti diagnostic scripts.
BF: fix nasty bug for orientations and 0 columns

Getting orientations for columns of all zeros in an affine resulted in
numpy svd hanging.  I realized in the mean time that the io_orientation
function was not returning the correct number of rows.  Extend tests,
fix, improve docstrings.
RF+DOC: remove unused _ornt_affine function

Remove unused function and expand docstrings for the orientation_affine
function, because it sure is confusing.
RF: rename orientation_affine to inv_ornt_aff

The original name was very confusing. Add deprecation warning attached
to old name.
RF+TST: make big_bad_ulp less likely to / 0 error

Add test for this (test) function.
Merge pull request #125 from matthew-brett/pydicom-0p7-fixes

BF: make compatible with pydicom 0.9.7

Pydicom 0.9.7 returns some fields as Python Decimals, when previously
they were floats. This causes a mess when using values in an array,
because the array becomes objects rather than floats, and, well, it
doesn't go well. Tests pass for me with pydicom 0.9.5 through 0.9.7
with these changes.
Merge pull request #124 from matthew-brett/checkfor-missing-scripts

RF: refactor installation checks to check scripts

Rewrite of testers module for clarity, in part. Add a routine that
allows us to check if any scripts have been missed in the installation.
Add this to the Makefile as a target and to the release checklist.

Refactor nifti diagnostic script, rename to nib-nifti-dx

Add nib-dicomfs, nib-nifti-dx to setup.py
RF: followlinks optional for dicom file system

followlinks keyword argument to os.walk was causing an error in python
2.5.  Maybe it should be optional anyway.
Merge pull request #129 from matthew-brett/optional-dicomfs-followlinks

RF: followlinks optional for dicom file system

followlinks keyword argument to os.walk was causing an error in python
2.5. Maybe it should be optional anyway.
Merge pull request #130 from matthew-brett/robust-tested-bbulp

RF+TST: make big_bad_ulp less likely to / 0 error

Add test for this (test) function.
BF: use smaller float type for rounding error test

ulp rounding error coming back as biggest float type.  This can give
very slightly different answers from error predicted from tested float
type.  Convert to tested float type for test.
Merge pull request #128 from matthew-brett/fix-orientation-hangs

BF: fix nasty bug for orientations and 0 columns

Getting orientations for columns of all zeros in an affine resulted in
numpy svd hanging. I realized in the mean time that the io_orientation
function was not returning the correct number of rows. Extend tests,
fix, improve docstrings.