Implement find sort and cursor sort with list. Also, stub out collection ensure_index and cursor close.
Add unit tests
Merge pull request #30 from craigahobbs/master

A few mongomock additions
Acknowledgement
Merge branch 'master' of https://github.com/vmalloc/mongomock

Conflicts:
	mongomock/__init__.py
	tests/test__mongomock.py