#14 Turning off glyph normalization

[vISTe]

Currently, all GPU glyphs for DTI are normalized. However, for certain applications it might be useful to turn this normalization off. Normalization is done in "tensorglyph.vert"; turning it off would be fairly straightforward.
A potential downside is that the range of tensor values seems to differ from DTI data set to DTI data set. As a result, turning off normalization of GPU Glyphs may result in very small tensor glyphs for some data sets, and huge glyphs for others. A better option might be to normalize the glyphs for the entire image, rather than locally. In other words, all eigenvectors are divided by the length of the largest eigenvector in the entire image.