create shell/command line receptor

[zippy]

This is a feature/use-case that requires integration of a bunch of issues.

We'll start with two commands: time & receptors, the first just gets the time from the clock receptor and sends a text representation to the stdout receptor, the second sends a text representation of the receptors to the stdout receptor kind of like unix ps

The intentions here are:

• to clean up issues with Unix File edge receptors (see create edge receptors for unix Files & in/out #15) - done
• to work process thread management between various threads that should block while waiting for each-other in the vmhost process queues (see vmhost process/thread management #22)
• to get looping (replication) into the instruction set (see Add looping/replication instruction #26) - done enough
• to exercise receptor integration, i.e. planting listeners and getting responses back, this includes adding code for long-term vs. single reply listener requests (see Add plant listener instruction #28)
• to figure out shared vocabularies between receptors (see implement shared vocabularies #24) - done enough
• to take next steps with scaping, i.e. so the receptors command can return an ordered list of active/non-active receptors by cpu accounting (see collect processing time accounting for receptors and flux entries #37 & Next scape steps #38) - moved to create vmhost admin protocols #67

[zippy]

64c6012 adds the basic framework and spec for this feature. Most things still missing, but now we've got something to build on.

[zippy]

It turns out that we don't actually need replication (#26) to work, rather we need to get expectations/action cleanup #19 working, for the shell to accept multiple commands. This is because we implement it not as a code loop but as actions fired on incoming COMMANDs on the flux.

Actually, replication is used inside the stream-edge-receptor, which hands LINEs off to the shell receptor, so we did need it after all.

[zippy]

as of 94362e4 this works much better. clock receptor actually returns the current time which then gets sent to the std-out receptor, and we have a scaffold cheat in place for the receptors command too, and this all works in the stand alone ceptr executable!

this ticket will be marked finished and the remaining items broken out into their own tickets.