Attempting to insert a table at the end of the last item in a list sometimes inserts the table after the list

This bug deals with the new tables in list feature added in #404.

This might be related to the two rows of spacer issue in IE8 also addressed in #406. 

To reproduce:

1. Start with this [unit test](http://192.168.1.72:8080/test/unit/index.html?filter=list-indent_outdent%3A%20First-level%20no-sublist%20previous-sublist&jquery=1.8.0)
2. Put your cursor right after the `8`
3. Insert a table
4. Insert another table
5. Move your cursor to the second "row" of space after the last table
6. Insert a table

Instead of being inside the `li`, this new table gets put entirely outside the list. The correct behavior would be for the table to be inserted inside the `li` after all of the other tables already within the `li`.