output api calls when no outputs connected

[guruofquality]

Update topology tells the block it only has as many outputs as are actually connected. This means, no connections, no output ports.

Users may want to write work routines that look and operate as if a port was connected, even if its not. Messages and buffers just dereference off into the ether if nothing is connected.

However, currently if a user expects an output port, but nothing is connected, the code will cause a segfault calling into the API with an out of range index. Since the internal structures are size zero...

[guruofquality]

this applies to inputs too now that we have an api to post to inputs