When.java - modified some() functionality to behave the same as when.js when a null list is passed.
When.java - added overloads to any() without all the callbacks
When.java - added overloads to all() without all the callbacks
Renamed Value<T> -> ValueHolder<T> and Reason<T> to Value<T>
Changed onProgress callback from Runnable<TProgress, TProgress> to Runnable<Value<TProgress>, Value<TProgress>> to allow passing exception information.
When.java - implemented yield().  Exposed yield/always/otherwise via a new PromiseExt<TResolve, TProgress> interface extending the regular promise interface.  Ported unit tests.
Optimized imports