Added  'debug' memory profile option flag

When building, use the 'debug' tag to build with additinoal commandline options
Added CPU profile option
Implemented streaming of serialized results
Support for fully-streamed seals.

The great thing is that this makes the code so much more readable !
Failiing destinations will not be written to anymore by the gatherers.

This makes writing to destinations that are already filled with similar files
fail much faster,  and much more gracefully.
Improved bookkeeping
Added feedback channel between gather and generate.

That way, gather can let its generate know that all destinations failed
and read can be aborted.
Fixed incorrect handling of source/destination path filtering