TODO for 0.9.8
   
   - URGENT: Change signature of interruption related functions in VM; sleep() must
             be fixed to respect interrruption protocol.
   - URGENT: New service model with service factory function.     
   - URGENT: New GarbagePointer model to allow passing foreign types.
   - URGENT: virtual constructor in sequences to allow them to build an empty copy.
   - URGENT: Break URI::UserInfo internally in user and password fields.
   - URGENT: Finetune continuations: be able to change parameters after the call.
   - Move dictionary find methods to standard sequences.
   - Expansion of the Tokenizer (with custom recognizers) and deep testing.
   - Provide Stream interface to Sockets.
   - Native support for big numbers.
   - Type contracts.
   - New, more flexible compiler/module pair, and revision of the link
     process.
   - Better Parallel constructs.