IQ streaming demo works on SF2

* Turn off mock as DUC works again.
* Improve poll logic.
* Pretty print last driver error in stats.
* debugfs # bytes written file for integration testing.
* Move back to 10MHz clock.
* Update peripheral addresses for smartfusion2.
* TODO: transmitter clearly working but PLL lock test is flakey.
* Move to using embedded RAM in FIR blocks.
* FIR now uses MACC DSP resource.
* Copy RAM implementation from DCC214 project.
* Fix HDL tests to work with new FIR implementation.
* Auto-build libevent; turned on unix daemon sockets.
* New reactor & daemon based on libevent.
* Intergation tests for the reactor.