fixed factor signature for applicative exercises
Omit an optional type variable of the Stream.filter method.

The type variable [B] of the fpinscala.lazyness.Stream.filter method
can be omitted.
08.answer.scala was the same as 07.answer.scala for chapter 9
fix for Traverse.mapAccum
Issue #334
Simplify answer to exercise 5.2
Prevent unnecessary evaluations

Previous implementation of drop did not handle 
    
    Stream.cons(0, ???).take(1)
Proper comments on take(n) and drop(n)
fpinscala-parallelism: Explains that the example map2 is semantically incorrect
Add traverse and sequence signature.
Merge pull request #344 from ralphcollett/master

Add traverse and sequence signature.
Update 01.answer.scala
Merge pull request #343 from mosesn/par-correct

fpinscala-parallelism: Explains that the example map2 is semantically incorrect
Merge pull request #338 from mlundela/patch-1

Simplify answer to exercise 5.2
Merge pull request #335 from jeremystone/master

Issue #334
Updated answer file for stream take/drop
Merge pull request #329 from abo64/mapAccum-fix

fix for Traverse.mapAccum
Upgrade to 2.11.4 and added travel build
Merge remote-tracking branch 'origin/master'
Merge pull request #324 from adamw/patch-1

08.answer.scala was the same as 07.answer.scala for chapter 9