Reimplement the 'single' operator
Add first, last, single to rxjava-scala
Throw NoSuchElementException in the first, last and single operators when the Observable is empty
Rename OperationFirstOrDefaultTest and OperationLastTest to OperatorFirstOrDefaultTest and OperatorLastTest
Fix clojure test
Fix tests in rxjava-math
Merge branch 'master' into single
Fix typos
Merge branch 'single' of git://github.com/zsxwing/RxJava into merge-967

Conflicts:
	rxjava-core/src/main/java/rx/Observable.java
	rxjava-core/src/main/java/rx/operators/OperationSingle.java
	rxjava-core/src/test/java/rx/operators/OperatorLastTest.java
Merge pull request #1051 from benjchristensen/merge-967

Manual Merge #967