Fixed QuestionManager.scala, implemented TraversableCollection.scala instead of
nondeterministic finite automata

BUG / FIX: TraversableCollection.scala can't work with TraversableFactory, app crashes with ClassDefNotFound.
The same implementation works in Scala REPL, so it's Scala-Android composite bug. Right now the TraversableCollection.scala only implements Traversable

Added 'Breakout two-choice question' type

Cleaned up the project file layout