util: In MemoryContentCache, added unregisterAll.
unit-tests: In TestNameMethods, update Prefix and Subname tests to the PyNDN version.
Merge branch 'chrono-sync2013' of https://github.com/zhehaowang/ndn-js into zhehaowang-chrono-sync2013
index.js: Don't export DigestTree since it isn't part of the public API.
node/tests: In test-chrono-chat-protobuf.js, simply require("protobufjs"), same as for sync-state.js, etc.
sync: Update the copyright header to say "Lesser" General Public License.
tests: In ChronoChat tests, add copyright header.
Merge branch 'zhehaowang-chrono-sync2013' from Zhehao's pull request, plus a few minor changes.
index.js: Temporarily remove ChronoSync2013 until it is changed to dynamically load protobufjs.
chrono-sync2013: Require protobuf locally; add SyncState class to conform to CCL API; test-chrono-chat:Use ChronoSync2013.SyncState for sendInterest method; index: enabled ChronoSync2013