Add a second example for the filtering & collecting test.
Add another filter example.

Conflicts:

	src/main/java/org/adoptopenjdk/lambda/tutorial/exercise2/ElectoralDistrict.java
clarify what I'm talking about when I say inference 'is no there yet'
Remove unused imports in uncompleted branch.
Add javadoc for the final unit test for filtering.
Update README.md
Replace all anonymous implementations of FeatureMatcher with call to factory method given an extractor function.
Add a third exercise: mapping.
Add three tests for mapping behaviour.
Make it clear method returns a set. Also use a feature for a better test failure message.
Update README.md
Update README.md

Added info on getting lambda jdk and version compatibility.
Add javadoc to each of the methods under test to repeat what is expected of them.
Merge branch 'master' of github.com:AdoptOpenJDK/lambda-tutorial
Update README.md
Update README.md

(try to) fix markdown for linking to anchor in same page.
Fixes #1 and Fixes #2 + some additional small Javadoc patches
Merge pull request #3 from karianna/master

Fixes #1 and #2 + some Javadoc patches
Fix #4 Maven POM enhancements
Fixes #8