 * functional
 * best practices
 * app composition
 * implicits
 * java interop
 * actors
 * streaming libraries
 * json
 * play
 * sbt
 * using traits
 * the cake pattern 
 * variance, type bounds
 * typeclasses
 * different test libraries, scala check
 * collections
   * lazy streams
 * concurrency, schedulers, futures, promises

 * [x] case classes 
 * [x] pattern matching
 * [x] typeclasses 
 * [ ] concurrency, schedulers, futures, promises 
 * [ ] sbt
 * [ ] functional
 * [ ] best practices
 * [ ] app composition
 * [ ] implicits
 * [ ] java interop
 * [ ] actors
 * [ ] streaming libraries
 * [ ] json
 * [ ] play
 * [ ] using traits
 * [ ] the cake pattern
 * [ ] variance, type bounds
 * [ ] different test libraries, scala check
 * [ ] collections
   * [ ] lazy streams

Reorder and make into task list.
Reorder and make into task list.