Increased wait time for serial response

Tested the auto baud selection, firmware version reporting and device
settings confirmation with a JeeLink v3 (rf69cw) on both windows and
linux, I found the serial responses were not consistent causing errors
this was eliminated by increasing the wait times to 2 secs. The
"Jeelink" devices seem to function identically to "rfm2pi". (tested
using RF12demo.12 only)
Separated "OK" and RSSI handling

Some devices may use the leading "OK" without RSSI eg rfm12 jeelink
running stock firmware.