Initial implementation of Label images. Very rough right now.

fsl/data/strings.py

fsl/fslview/displaycontext/__init__.py

fsl/fslview/displaycontext/display.py

fsl/fslview/displaycontext/labelopts.py

fsl/fslview/displaycontext/modelopts.py

fsl/fslview/gl/__init__.py

fsl/fslview/gl/gl21/__init__.py

fsl/fslview/gl/gl21/gllabel_frag.glsl

fsl/fslview/gl/gl21/gllabel_funcs.py

fsl/fslview/gl/gllabel.py

fsl/fslview/gl/globject.py

fsl/fslview/gl/shaders.py

fsl/fslview/gl/textures/__init__.py

fsl/fslview/gl/textures/lookuptabletexture.py

fsl/fslview/layouts.py

fsl/fslview/lookuptables.py

fsl/fslview/luts/harvard-oxford-cortical.txt