BUG: Atlases need to be transformed with '-interp nearestneighbour`

[larsoner]

In

infant_template_paper/template_building.py

Lines 443 to 447 in d907822

	command = ("flirt -applyxfm \\\n" +
	" -in {} \\\n" +
	" -ref {} \\\n" +
	" -init {} \\\n" +
	" -out {}")

we need to use nearest neighbor interpolation because we need an array of the same set of ints back for the atlas to be usable. IXI for instance has values 0-83, but after flirt it has values 0-255, which is not good.