Make sortBy stable
Allow passing a property/method name as a callback; detect when it's an observable and don't create any unnecessary computed
Handle moves correctly for sortBy, now that it's stable
Fix sorting issue with sortBy

Caused by the fact that it does a binary search for the new index
before it removes the old one. So it has to be decremented if it's
further down the array.
Make any/all work when values are moved
Make sure 6eeefeb only applies to value mutations
Fix chained filtering behavior; no longer pass offset to valueMoved; expect returned changes to always use immediate indexes, and fix them to use absolute indexes afterward
Remove unnecessary argument
Make sure value mutation changes also get converted to absolute indexes
Add a spec for map -> map
Remove reliance on internal trackChanges function
s/isObservable/isComputed/
Improve minification slightly
Add groupBy
Factor out some common test data
More groupBy specs
Bump version to 0.3.0