Add zip of a collection of Observables
Unit testing what happens when the number of arguments doesn't match the number of observables.
Adding zip(Ob<Ob<?>>)
Update Observable.isInternalImplementation, get rid of NullPointerException

NullPointerException has been encountered during my tests. It is because java.lang.Class.getPackage() may return null "... if no package information is available from the archive or codebase" (documented feature).
Merge pull request #302 from rgerasimen/patch-1

Update Observable.isInternalImplementation, get rid of NullPointerExcept...
Merge pull request #290 from abersnaze/issue103

Issue 103