updated a test and added another one, trying to get the expected behavior right
made 'next' more typesafe
An attempt at implementing the correct combineLatest semantics. The
tests do pass again now (they had to be adapted too).
Fixed javadoc and comments, cleaned up a bit, and tried to fix
synchronization.
Whoops, generics not allowed in @see javadoc...
Merge pull request #207 from jmhofer/master

Implemented combineLatest semantics