first draft to final orientation fix:

will include:
  *full nii support
  *volume displayed in RAS space
  *volume resliced trhough TRUE axial, coronal and sagittal planes (arbitrary reslicing later on)
  *true XYToIJK/RAS in 2D views
  *reslice on deman ofr better perf
wip
Incorporate the center of the volume when loading NII files which now can match trackvis and freesurfer meshes (under perfect conditions).

Perfect conditions are:
a) volume is not sheered
b) the trk file has a correct vox2ras transform or the coordinates are in RAS space
Some experiments with XIO and webworkers.
wip: arbitrray reslicing
wip
Remove obsolete check on the DOM element in X.interactor.
Only add a null check when assigning a dom element to an interactor.
Export several properties of X.texture and X.slice.
Reset flag for mousewheel observation.
Add the X.texture.grayscale flag to support 1 channel textures without overhead of mapping to RGBA.
Merge branch 'webworker_xp'
Avoid check on the dom element in X.interactor.
fix for parent element shifting
Merge pull request #129 from ahartung/master

progress bar parent element shifting fix
use quaternions to rotate plane to XY
niftii parser was always setting orientation values to first row
add 2d bounding box

todo: get spacing to be able to iterate.

then: create slices :)
bit slow and textures are incorrect in some orientation

need to take spacing into account
bug fix: string conversion to number failure