Updated to warn user when backgrounds don't exist.
Merge branch 'fs20_datastruct'

Conflicts:
	E200_DRT.m
	plotpanel.m
Merge branch 'fs20_datastruct'

Conflicts:
	.gitmodules
	aux_functions/ButterflyEmittancePython
	plotpanel.m
Updated to fix several issues
Updated to latest butterfly analysis.
Updated to ignore .DS_Store, *.orig
Merge branch 'fs20_datastruct'
Updated gui slider handling.