Adding more examples of high-order functions, lambda, including an Anagram implementation.

This commit adds examples collected from https://github.com/edalorzo/jdk8-preview, and
added comments to the examples. Based on examples, I first implemented the Anagrams problem
using POJOs, in the class StreamBulkOperationsMapFunction with some help from stackoverflow.

http://stackoverflow.com/questions/21978653/java-8-jdk8-streams-functions-map-reduce-to-group-liststring-into-mapstring