modify exposure time input

[astronomerdave]

ngps-observe has a text entry box to the right of the progress bar, which is used to modify the exposure time during an exposure. This should be labeled, minimally, and perhaps needs a send button, or does the exptime get modified as soon as you hit return? This should be greyed-out when not exposing since it is not applicable except during an exposure.

[chazshapiro]

What is the sequencer command to send? I assume GUI is talking to sequencer and not camerad directly.