Rename 'data' into 'imageData'

As agreed on NIDASH-DDWG call 10/02/2014.
Proposed 'image data' modelling

As discussed on March 26th
Rebasing
Remove brain from attribute names

`targetBrainIntensity` becomes `targetIntensity` and
`measuredMedianBrainIntensity` becomes `medianIntensity`
`Image data` updated to `data`
Rename 'data' into 'imageData'

As agreed on NIDASH-DDWG call 10/02/2014.
Proposed 'image data' modelling

As discussed on March 26th
Remove brain from attribute names

`targetBrainIntensity` becomes `targetIntensity` and
`measuredMedianBrainIntensity` becomes `medianIntensity`
`Image data` updated to `data`
Capitalise "prov:Collection"
Update serialisations
Remove "image" from data label
Update serialisations
Merge pull request #32 from cmaumet/spmDataScaling

WIP: Data scaling modelling