Set final.
Add tests to verify that takeWhile operator use correct positional index even in parallel.
Add tests for takeWhile operator.
Add tests for sequential skipWhile operator.
Refactoring: Use factory instead of constructor.
Implements skipWhile operator that is executed in parallel.
Change interface ParallelSeq into a class that prevent implement by user.
Refactoring: Use factory instead of anonymous class.
Refactoring: Use assertion method instead of assertTrue.
Add tests based on new javadoc.
Implements toMap operator that is executed in parallel.
Add utility method.
Refactoring: use singleton.
Refactoring: use forAll operator.
Refactoring: optimize forAll operator for empty.
Refactoring: remove unnecessary return value.
Fix javadoc.
Add overload of toLookup.
Fix javadoc.
Fix NPE description in javadoc.