replace tribe format with mat

use popular mat format which is compressed, fast, and easily extended,
remove old proprietary tribe format
addLayer uses input parsing
Merge branch 'Development' into validateInputs
addNodes uses input validation
addTrack uses input validation
layerRGBA uses input validation
projectVolume uses input validation, avgIntensities option
setMaterial uses input validation
simple tests
bug fix
intensity fxn helpers
comment fix
project volume accepts input for interpolation method
update comment
update GUI for obtaining interp method
add test for interopt
Merge branch 'interpOpt' into threshOpts
values below threshold set to surface color
range shown on projection
update prompt opts