Makes MVL and TinyXML2 optional.
Reenables SensorViewer.
Makes TinyXML2 really optional. #ifdefs in DeviceRegistry.
Fixes SensorViewer logging before plotting.
Some small cleanups and error checks in Pb Reader
Reformats PrintMessage.cpp
Error checks in ProtoReaderDriver
Adds AndroidIMUDriver
SensorViewer defaults to AndroidIMU on Android.