uart: feed rx data to both lua console and on-data callback

[jasaw]

UART on-data example usage with run_input set to 1:

uart.on(0, "data", 0,
  function(data)
    print("receive from uart:", data)
end, 1)

According to documentation for run_input:

If 1, input from UART will go into Lua interpreter, and run.

Currently, UART data either go into Lua interpreter or on-data callback. This PR fixes that.

[jasaw]

@jmattsson I can't assign you as a reviewer, so I just ping you here instead.

[jmattsson]

This looks like a needed alignment to the docs (and I suspect this might be my bug in the first place - apologies).