Making an Archive from scratch makes invalid Alembic files that crash Maya and abcecho

[alex-v-dev]

Hi again !

Here's an example :
`
import cask

arch = cask.Archive(fps=24)
arch.set_start_frame(14)

arch.write_to_file("D:/TestTS.abc")

saved = cask.Archive("D:/TestTS.abc")
print saved.start_frame()
print saved.end_frame()
`

Running this, in my case, makes and Archive that starts at frame 14, but ends at frame 13. The archive is invalid, it will crash Maya and AbcEcho. Any ideas ?

[rsgalloway]

This has never been very robust, and probably needs work. For now, I'd suggest creating your own timesampling object and then setting it on the archive with add_timesampling(). You can refer to the cask unit test code, e.g. cube_out(), for example code on creating timesampling objects.