enh: first pass at the cifti2 reader
fix: remove cifti element spec
enh: cifti writer enabled
ref: initial refactor towards cifti datatypes
fix: updated to reflect latest CIFTI-2 spec and nifti extensions
tst: added test data
fix: voxelindicesijk initialization, header version check, typo in error message
fix: version number for looseversion
tst: added basic io tests
fix: removed redundant file writing
fix: unicode in docstring
fix: py3k bytes reading for numpy
fix: move cifti to check to top level function

- create property is_cifti
- rename conversion function as_cifti
fix: started cleaning up classes - removing prints and adding tests
Made fileno transparent
Merge branch 'enh/cifti2' of github.com:satra/nibabel into fix_mmap