observePathValue -> observePath
fix pathValue -> path
new api
added support for dirty checking
path should use ===, test
add d8 impl of console.time
added lenient evaluation of denegerate cases
added setValueAtPath plus tests
correct polyfil for Map & Set
added ChangeSummary.CallbackRouter
added (un)observeObject to CallbackRouter
use weakmap for router if available, continue delivery until no changes for dirty-check mode
Optimizations for the dirty-checking path. Including the case where path observation is overwhelmingly used
clean-up from review comments
use createObject for extending classes
Fix issue where multiple changes to the same model skipped later changes

ObjectTracker checkPathValues has side effects so we need to make sure it is
not skipped due to JS shortcutting logical or expressions.
Merge pull request #4 from arv/fix-multiple-changes

Fix issue where multiple changes to the same model skipped later changes
removing MDV example
remove more MDV leftovers
now using mocha/chai for testing