Removal of logging.NullHandler causes crash on startup if sgtk is loaded

[Mitja Müller-Jend]

In the case that Shotgun toolkit is loaded with the node_table and the node_table is saved to the layout, Nuke crashes to desktop on startup.

Procmon indicates a buffer overflow when importing model.py, but I don't understand how anything of it is related to the NullHandler.

As a quick fix, I'll add the NullHandler back in (removed in 2.1.0) while I try to come up with a way to debug the crash.

[Mitja Müller-Jend]

Merged in 53-revert-removal-of-nullhandler (pull request #9)

Fix crash when loading node_table on startup with sgtk

Closes #53

→ <<cset a3bb36bf1a02>>