Changes to be committed:
	modified:   src/analyserwindow.h
	modified:   src/analyserwindow_refresh.cpp
	modified:   src/analyserwindow_signal_data.cpp

Fixed a critical bug that caused FAST to crash when calculating the branching
fractions for all levels in AnalyserWindow::on_data_output_results. The problem
was caused by an out-of-bounds reference to LineBoxes.