utils: In NameEnumeration, use expressInterest with callbacks, not Closure.
util: In NameEnumeration, define functions for onData and onTimeout in the constructor.
Merge branch 'master' of https://github.com/named-data/ndn-js

Conflicts:
	build/ndn.js
	build/ndn.min.js
	js/util/name-enumeration.js
re-remove requires from name-enumeration.js