[#10] Added some basic support for extensions on stores, which will listen for updates. First extension is one to insert timestamps on objects.
[#10] Merging 0.2.0 release changes into extension branch
[#10] putmany() is untested. Removing for a cleaner foundation. Will re-add later and better.
[#10] First accurate tests of extension event delegation
[#10] Refactor the Timestamp extension into Default and Timestamp extending that.
[#10] Improving test coverage of Default extension