push with a shared scalar bombs:
 push( @shared,$shared );    # bombs
 push( @shared,$shared.'' ); # works
Haven't got a clue why.

optimizations:
- Storable::freeze/thaw not always needed: check Thread::Serialize
- change remote function names to command numbers
- allow for unix domain sockets as transport medium
- allow for shared memory as transport medium (how will we fix blocking?)
