Map and weigh pixels after capturing from all projectors
Add some debug output and improve calib opt GUI
Remove parameters from CalibData::triangulate

This method now directly accesses the global reproj module pointer,
cast to a ReprojSimpleModule pointer. This is acceptable because this
CalibData will only be used within a ReprojSimpleModule, not any other
kind of reproj module.
Skip mapping pixels that are too dark
Add a GUI option for the min calib intensity
Print number of skipped pixels due to too-dark calibration
Fix a crash when calibrating after generating compensation images

One line of code fixed this as well as a memory leak.
Add button to generate error images

The error image is the difference between the target image and the
captured image with combined compensation projection.
Fix minimum brightness check to use each channel

Previously it was using the getGrey method, which returns an apparent
greyscale intensity based on human vision using magic numbers. Not what
we want.
Fix a crash with calibrating after generating weight images

This happened before with generating compensation images for the same
reason. What was I thinking when I wrote this code??