autoclose: Fix crash due to use-after-free.

The signal handler for "sci-notify" needs to be disconnected when the
document is closed because the handler might be called afterwards but
with already freed user data.
autoclose: Rename signal handlers to better fit the signals they're connected to.
Merge pull request #1 from kugel-/autoclose-v0.2

Autoclose v0.2
Homogenize checks, fix doc checking, remove define warnings
Merge pull request #115 from scriptum/autoclose-v0.2

Autoclose v0.2 - use-after-free fix