RxJava2 Migration: Return single/maybe where appropriate. (nytimes#185)

* RxJava2 Migration: Return single/maybe where appropriate.

* Remove no longer used class.

* Pull in the fix for nytimes#181 from develop.

* Re-iterated solution nytimes#181 issue.

Version 2.0.4

Version 2.0.3

Version 2.0.2

Version 2.0.1

Version 2.0.0

Version 1.0.7

Version 1.0.6

Version 1.0.4