Merge Request #8 - May

Small Changes

• qi::waitForAll now returns a cancelable FutureSync
• Add qi::Future::andThen which calls a callback only if the future succeeds
• Python: add Future.unwrap
• Python: add Future.then
• Python: add Future.andThen
• Python: add futureBarrier
• Support cancelation of remote calls
• Make qilaunch use a prefix when publishing logs to LogManager

Bugfixes

• Remove lock from async version of qi::log
• Fix qilaunch abort when run in standalone mode