Use django-nose test runner
Add coverage directory to the gitignore
Rename 'examples' directory to the 'tests'
Rename applications in test settings
Convert tests from doctests to the unit tests
Refactored/simplified update_on_delete
Put «collection changed» attribute into an internal cache
Skip almost all the test for a while -- I'm going to forbid negative positions
Don't capture stdout
Remove unused import
Add support for "at the end" insertion -- last position will be calculated by the database itself. This is useful when we have a lot of concurrent transaction each trying add items to the same collection
Bump version: increase main number to be distinguished from the main repository
Merge branch 'release/1.4.6'

Conflicts:
	positions/examples/generic/tests.py
	positions/examples/lists/tests.py
	positions/examples/nodes/tests.py
	positions/examples/photos/tests.py
	positions/examples/restaurants/tests.py
	positions/examples/school/tests.py
	positions/examples/store/tests.py
	setup.py