glib bindings issues

[Havoc Pennington]

Hi,

"make check" in glib wasn't working for me, due to GPtrArray append not 
copying the string values passed in. I added more details in a comment 
and also a g_assert_not_reached() to be sure it crashes for everyone 
instead of just corrupting memory, but someone who gets this code needs 
to debug.

There's also another likely bug in GSList handling, I added an assertion 
and comment there as well.

Havoc