This automatically loads settings, zerver.models.* and
zerver.lib.actions.* when you start `manage.py shell`, which should
save a bit of time basically every time someone uses it.
Fixes#275.
This could potentially help with debugging exactly what happened with
some issue down the line.
(imported from commit cc7321d742875b644d4727a084b462dcd01dcf10)
This includes a hack to preserve humbug/backends.py as a symlink, so
that we don't need to regenerate all our old sessions.
(imported from commit b7918988b31c71ec01bbdc270db7017d4069221d)
I first made --traceback the default in my patches to django, but this
broke several regressions tests (when Luke built .deb packages), so he reverted that change,
and I'm putting this default into our manage.py instead
(imported from commit 460253561e637d8a6692c68bbd3859f266dbf83d)