Updated rtl build instructions
Force performance data to be usec, too hard to compare usec, msec, nsec
ProducerConsumer updates

Switch to support moveToThread and QThread subclass models.  Doesn't seem to make a difference, so default to moveToThread.

Switch to use blocking acquire/release.  Blocking performs better.

Cleanup all over, using callbacks instead of DeviceInterface methods
Update to new ProducerConsumer callback architecture
Lots of tweaks to rtl2832, but still using more CPU then 2.0.0.  Compare ProcessIQ performance next to see if we introduced problem there