gras: moved flush output to consume function in output queues

This cleans up some code in block actor.
The message sending code is now in task_main,
and the consume routine is now the shared one.
gras: fixed buffer inlining with explicit support in buffer queue

Rather than push the inlined buffer into the BufferQueue,
the output buffer queues wrapper explicitly supports
holding onto the inlined buffer.

This is because BufferQueue overloads generally do a token check
so they only accept buffers that they are in charge of.

fixes #79
gras: update extras submodule for opencl
gras: simplify PMC registration with new macro
Merge branch 'master' into theron6_work
gras: updated Theron submodule