Block output socket value attribute not populated

[Poindexter Frink]

If a socket is declared:

<variable socket="out" info="Out" value="0"/>

There is no corresponding value assignment in the generated init_dsp_objects().

Even though it should be expected that blocks assign their outputs during the first function execution, the population of the default value would allow a block to be designed to conditionally set its output without the need for a state variable or a value assignment in the block function.

In short, this could save 1 instruction per block per sample and potentially save memory used as state variables.

[Poindexter Frink]

Adding support for "editable" and "value" to output sockets would allow block designers to have configurable default values with no memory or processing penalty.