[usdview] add --camera cmdline arg

[pmolodo]

Description of Change(s)

Allows choosing of what camera to use when opening the scene

Included Commit(s)

• f2f5e99

Fixes Issue(s)

• None, perse, but there was a TODO note about not hardcoding the default to be a pixar-specific name, which this effectively does

[sunyab]

Passing along some code review notes:

Hi Paul,
This is great! The one limitation is that there may commonly be multiple cameras in the scene with the same (prim) name. I'd suggest allowing (and documenting) --camera to accept either a simple name or a full prim path, then matching by name or path, as appropriate, in mainWindow.py . (Owning also that the camera menu has the same issue - if there are multiple cameras with the same name you'll see the name repeated but won't know which is which - needs fixing!)

Thanks - I know alot of folks are going to find this really useful!

[pmolodo]

Added in the ability for the command-line arg to take full prim paths, as requested. Didn't touch the handling of duplicate camera names in the UI menu - will let you folks decide how you want to deal with that.

Lemme know if you need anything else!

[jtran56]

Filed as internal issue #147138.