IOS devices with a dash in UDID were still not working even after recent changes.
This fix should address the issue. This change has in fact been tested against such a device and is working.

Change was to use the newer API from Apple that was being used to list devices to also select the device.

Previous "fix" to strip out UDID broke functionality for all devices with a dash in their UDID.
This change fixes that bad fix...

Added 'list' command to list available IOS devices that video can be streamed from.
Also added build time variables for version information.

Updated to always send at least a frame per second even if the screen has not changed. This is helpful so that an image always appears in STF on first connecting, otherwise no video will appear until something changes on screen.

Nanomsg was not actually sending when it was called within the callback from AVFoundation. That context interferes with nanomsg somehow. Altered the code to use an inproc nanomsg queue to first transfer the jpeg frame to the main thread and then send out to tcp via nanomsg from there. That works.

Also fixed a small bit of uclop; it wasn't handling flags appropriately.

Initial version. Still frame detection from h264_to_jpeg. CLI option processing from uclop.
TODO: Implement frame skipping.