Release v1.2.1

• Added pyqtgraph HistogramLUTItem to the B-scan and enface displays
• Fixed bug which made it impossible to view the scan pattern signal plot

Release v1.1.1

• Fixed issue which caused deadlock on acquisition stop
• Fixed start trigger behavior
• Refactored CircAcqBuffer
• Fixed undefined behavior on NI scan engine shut down

Release v1.0.1

Fix to backend loading. v1.0.0 cannot be run from dist.

Release v1.0.0

Qt 5.9.2 req